Claims:WE CLAIM
1. A polymeric blend composite comprising;
a. a poly(ether ketone) having an inherent viscosity in the range of 0.60 to 1.8 dL/g;
b. poly(2,5-benzimidazole). having an inherent viscosity in the range of 0.90 to 4.00 dL/g;
c. 0.5 wt% to 5 wt% of multi walled carbon nanotubes;
wherein the ratio of said poly (ether ketone) to said poly (2, 5-benzimidazole) is in the range of 60:40 to 90:10; and
wherein said polymeric blend composite is characterized by:
• having an electrical conductivity greater than 10-12 S/cm; and
• a storage modulus in the range of 2300 to 3000 MPa at a temperature in the range of 50 °C to 180 °C and 230 to 450 MPa at a temperature in the range of 200 °C to 300°C .
2. The polymeric blend composite as claimed in claim 1, wherein the ratio of said poly (ether ketone) to said poly (2, 5-benzimidazole) is 80:20 (wt/wt).
3. The polymeric blend composite as claimed in claim 1, wherein the weight average molecular weight (Mw) of said poly(ether ketone) is in the range of 80,000 to 1,10,000.
4. The polymeric blend composite as claimed in claim 1, wherein the inherent viscosity of said poly (ether ketone) is in the range of 0.70 to 1.2 dL/g.
5. The polymeric blend composite as claimed in claim 1, wherein the inherent viscosity of said poly (2, 5-benzimidazole) is in the range of 1.00 to 3.00 dL/g.
6. The polymeric blend composite as claimed in claim 1, wherein the bulk density of said poly (2, 5-benzimidazole) is in the range of 0.20 to 0.30 g/cm3.
7. The polymeric blend composite as claimed in claim 1, wherein the diameter of said multi walled carbon nanotubes is in the range of 8 nm to 20 nm and the length of said multi walled carbon nanotubes is in the range of 0.1 µm to 1.5 µm.
8. The polymeric blend composite as claimed in claim 1, wherein said multi walled carbon nanotube has an ID/IG value in the range of 0.9 to 1.1.
9. A process for preparing said polymeric blend composite as claimed in claim 1, said process comprising the following steps:
a) pre-treating multi walled carbon nanotubes to obtain pre-treated multi walled carbon nanotubes;
b) mixing a poly(ether ketone), poly (2,5-benzimidazole), and said pre-treated multi walled carbon nanotubes to obtain a powder dry blend; and
c) extruding said powder dry blend at a temperature in the range of 300 °C to 450 °C to obtain said polymeric blend composite in the form of extrudates and subsequently pelletizing these strands as granules, which are the injection molded or extruded or compression molded.
10. The process as claimed in claim 9, wherein said pre-treatment of said multi walled carbon nanotubes comprises the following steps:
i. ultrasonicating said multi walled carbon nanotubes at a frequency in the range of 15 to 25 kilohertz for a time period in the range of 10 minutes to 60 minutes to obtain uniformly dispersed multi walled carbon nanotubes; and
ii. drying said uniformly dispersed multi walled carbon nanotubes at a temperature in the range of 80 °C to 120 °C for a time period in the range of 1 hour to 48 hours under vacuum in the range of 1 to 700 mm of Hg to obtain said pre-treated multi walled carbon nanotubes.

11. The polymeric blend composite as claimed in claim 1, wherein said electrical conductivity of the composite blend is improved from 10-12 S/cm to 10-4 S/cm.
12. The polymeric blend composite as claimed in claim 1, wherein said storage modulus is in the range of 2305 MPa to 2892 MPa at ambient temperature.
13. The polymeric blend composite as claimed in claim 1, wherein said Storage Modulus is improved at 300°C from about 230 MPa to 388 MPa.
14. The polymeric blend composite as claimed in claim 1, wherein said MWCNTs in the range of 1.0 wt% to 5wt% improves electrical conductivity and Storage Modulus substantially.
15. The polymeric blend composite as claimed in claim 1, wherein the ratio of PEK/ABPBI varies from 80/20 by weight %.
16. The polymeric blend composite as claimed in claim 1, wherein the ratio of PEK/ABPBI is in the range of 60/40 to 80/20 by weight %.
17. The polymeric blend composite as claimed in claim 1, wherein said composite containing 5 wt% MWCNTs (0.1-1.5 µm length) with electrical conductivity greater than HDT of blend composition containing 0 wt% MWCNTs.
, Description:This is an application for a patent of addition to the Indian Patent Application No. 201821001494 filed on 12th Jan 2018, the entire contents of which are specifically incorporated herein by reference.
FIELD OF THE DISCLOSURE
The present disclosure relates to a polymeric blend composite and a process for preparing the same.
DEFINITIONS
As used in the present disclosure, the following term is generally intended to have the meaning as set forth below, except to the extent that the context in which it is used indicates otherwise.
The term “scaling law” as used herein refers to the functional relationship between two physical quantities that scale with each other over a significant interval. The ‘scaling-law’ is expressed by: sDC = s (p-pc)t where, p is the weight fraction of the filler, pc is the weight fraction of percolation and t is the critical exponent that is related to the system dimensions.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Poly (ether ketone) (PEK), belongs to the family of high-performance semi-crystalline thermoplastic polymers known as polyaryletherketones (PAEKs) having excellent thermal properties, mechanical properties, good chemical resistance, low moisture absorption, and therefore can be used as high performance material for high-quality applications. PAEKs generally have Tg values in the range of 140–180 °C, and melting temperature (Tm), in the range 300 to 400 °C. These polymers are insoluble in most common solvents at room temperature, except for strong protonating acids such as concentrated sulfuric, hydrofluoric, methane sulfonic and trifluoro methane sulfonic acids.

Poly (ether ketone)
Poly(2,5-benzimidazole) (ABPBI), represented by the molecular formula (C7H4N2)n, is insoluble in water, organic solvents and does not have a melting temperature. ABPBI cannot be melt-processed up to 520 °C, due to its high glass transition temperature (Tg) of 485 °C and the absence of Tm up to 600 °C. Poly (2, 5-benzimidazole) tends to decompose before melting. ABPBI is thus extremely stable up to 650 °C, but it is difficult to melt process. ABPBI is also highly resistant to most chemicals. In spite of possessing exceptional properties, it has not been fully explored as a polymer due to the difficulty in its processing. It is typically used as a solution cast membrane and has been evaluated as phosphoric acid impregnated proton exchange fuel cell membrane.

Poly (2, 5-benzimidazole) (ABPBI)
Typically, ABPBI is blended with binders, such as PEK, to make it processable. The blend of PEK/ABPBI thus formed has the properties of high performance material, and extremely high temperature stability. Further, the drawback of degradation of ABPBI is also eliminated.
However, the heat deflection temperature (HDT), and the DC electrical conductivity of PEK/ABPBI blend is low. Further, uniform blending of the PEK/ABPBI blend is difficult to achieve, which affects the stability of the obtained PEK/ABPBI blend.
There is, therefore, felt a need for PEK/ABPBI containing MWCNTs blends that mitigates the hereinabove mentioned drawbacks.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
It is an object of the present disclosure to ameliorate one or more problems of prior art and to provide a useful alternative.
Another object of the present disclosure is to provide a polymeric blend composite of PEK, ABPBI, and MWCNTs.
Another object of the present disclosure is to provide a polymeric blend composite of PEK/ABPBI/ MWCNTs having a high electrical conductivity.
Still another object of the present disclosure is to provide a polymeric blend composition of PEK/ABPBI/MWCNTs with higher storage modulus reflecting higher rigidity at higher temperatures than PEK alone or neat PEK/ABPBI blend.
Yet another object of the present disclosure is to provide a stable polymeric blend composite of PEK, ABPBI, and MWCNTs.
Another object of the present disclosure is to use PEK/ABPBI blend containing up to 5 wt% MWCNTs.
Still another object of the present disclosure is to provide a process for producing a polymeric blend composite of PEK/ABPBI/MWCNTs and injection mold and extrude these to give useful articles.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure provides a polymeric blend composite. The polymeric blend composite comprises PEK having an inherent viscosity in the range of 0.60 to 1.8 dL/g, ABPBI having an inherent viscosity in the range of 0.9 to 4.0 dL/g and 0.5 to 5 wt% multi-walled carbon nanotubes (MWCNTs). The ratio of PEK to ABPBI in the polymeric blend composite can be in the range of 60: 40 (wt/wt) to 90: 10 (wt/wt). The polymeric blend composite is characterized by having improved heat deflection temperature in the range of 170 °C to 240 °C, improved electrical conductivity in the range of 10-12 to 10-4 S/cm and improved storage modulus in the range of 2300 MPa to 3000 MPa at ambient temperature, and 230 MPa to 450 MPa at 300 oC.
The present disclosure further provides a process for preparing a polymeric blend composite. The process comprises pre-treating MWCNTs to obtain individualized, non-aggregated MWCNTs, and mixing predetermined quantities of PEK, ABPBI, and pre-treated MWCNTs to obtain a powder dry blend. The powder dry blend is extruded to obtain granules followed by injection molding method for preparation of useful articles.

The molded specimens so prepared are evaluated for electrical conductivity and storage modulus.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The polymeric blend composite of the present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1a illustrates a graphical representation of AC electrical conductivity versus frequency for PEK/ABPBI polymeric blend composite with various concentrations of MWCNTs (wt%) in the polymer blend composite;
Figure 1b illustrates a graphical representation of DC electrical conductivity versus various concentrations of MWCNTs (wt%) used in PEK/ABPBI polymeric blend composite;
Figure 1c illustrates a graphical representation of Scaling law for DC electrical conductivity in respect with various concentrations of MWCNTs (wt%) used in PEK/ABPBI polymeric blend composite;
Figure 2a illustrates a graphical representation of AC electrical conductivity versus frequency for neat PEK with various concentration of MWCNTs (wt%);
Figure 2b illustrates a graphical representation of DC electrical conductivity versus various concentrations of MWCNTs (wt%) used in neat PEK;
Figure 2c illustrates a graphical representation of Scaling law of DC electrical conductivity in respect with various concentration of MWCNTs (wt%) used in neat PEK; and
Figure 3 represents a graph illustrating the storage modulus of the polymeric blend composite of PEK and ABPBI (80/20 wt/wt) and neat PEK having varying concentration of MWCNTs (wt%) at different temperatures (200°C, 250°C, and 300°C) in accordance with the present disclosure.

DETAILED DESCRIPTION
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed elements.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
Currently, the blends of PEK/ABPBI have properties related to high performance material and efficient processing of ABPBI, when blended with binders, such as PEK. However, the HDT, the electrical conductivity and the storage modulus or rigidity of the known PEK/ABPBI blends is low, restricting their use in high end applications.
Therefore, the present disclosure envisages a PEK/ABPBI polymeric blend composite with MWCNTs having high electrical conductivity, high rigidity, and higher stability.
In an aspect of the present disclosure, there is provided a polymeric blend composite of polyether ketone/poly(2,5-benzimidazole) (PEK/ABPBI) containing a nanomaterial. The polymeric blend composite comprises PEK, ABPBI, and specially MWCNTs. In an embodiment, the nanomaterial is multi-walled carbon nanotubes (MWCNTs).
In accordance with the embodiments of the present disclosure, the ratio of PEK to ABPBI can be in the range of 60/40 to 90/10 (wt/wt). In an embodiment, the ratio of PEK/ABPBI is 80/20 (wt/wt). Poly(ether ketone) and Poly (2, 5-benzimidazole) (ABPBI) when blended, has properties related to high performance material and efficient processing. However, properties such as, electrical conductivity, heat deflection temperature (HDT), storage modulus, and the rigidity of known PEK/ABPBI blends are not of the desired level, restricting their use in high end applications such as connectors, thermal interface materials, heat sinks, electronics packaging, self-regulating heaters, PTC resistors, and in transport industry.
Therefore, the present disclosure envisages a PEK/ABPBI polymeric blend composite containing MWCNTs having comparatively high electrical conductivity, high rigidity, and improved stability.
In one aspect of the present disclosure, there is provided a polymeric blend composite. The polymeric blend composite comprises PEK having an inherent viscosity in the range of 0.60 to 1.8 dL/g, ABPBI having an inherent viscosity in the range of 0.90 to 4.00 dL/g and 0.5 to 5 wt% multi walled carbon nanotubes (MWCNTs).
In one embodiment of the present disclosure, the inherent viscosity of the poly (ether ketone) is in the range of 0.70 to 1.1 dL/g and the inherent viscosity of the ABPBI is in the range of 1.00 dL/g to 3.00 dL/g.
The weight average molecular weight (Mw) of the PEK can be in the range of 80,000 to 1, 10,000.
PEKs are high performance semi-crystalline thermoplastic polymers having thermal and mechanical properties. Further, PEKs have good chemical resistance and low moisture absorption, due to which the PEKs are used as important materials in various applications. PEKs have the glass transition temperature (Tg) in the range of 140 – 180 oC and the melting temperature in the range of 300 oC to 400 oC. Due to these properties PEKs can be transformed from the melt to glassy or semi-crystalline state depending on the cooling conditions. The temperature conditions affect the mechanical properties of PEK’s e.g., impact resistant, yield stress, and fracture toughness.
ABPBI is a solid, odorless, reddish brown colored thermosetting polymer having a bulk density in the range of 0.2 to 0.3 g/cm3. It is insoluble in water and an organic solvent even at high temperatures and does not have a melting temperature. ABPBI alone cannot be melt processed up to 520 °C due to its high glass transition temperature (Tg) of 485 °C and the absence of Tm up to 600 °C.
In accordance with the present disclosure, in one embodiment, the inherent viscosity of ABPBI is in the range of 1.00 to 3.0 dL/g. The bulk density of ABPBI can be in the range of 0.20 to 0.30 g/cm3.
Typically, the ratio of the PEK to the ABPBI can be in the range of 60/40 (wt/wt) to 95/5 (wt/wt). In one embodiment of the present disclosure, the ratio of the PEK to ABPBI in the polymeric blend composite is 80/20 (wt/wt).
Multi-walled carbon nanotubes (MWCNTs) in their disentangled and individualized state have tensile strength up to 100 GPa; and exhibits high aspect ratio, resistance to high temperature (beyond 500 oC), high strength to weight ratio (due to their low density), chemical stability, and thermal conductivities greater than copper and diamond. In accordance with the present disclosure the diameter of the MWCNTs can be in the range of 8 nm to 20 nm. The length of the MWCNTs can be in the range of 0.05 to 15 micron (µm). Preferably, the length of the MWCNTs can be in the range of 0.1 to 10 micron (µm), and the diameter of the MWCNTs can be in the range of 8 nm to 14 nm. In one embodiment of the present disclosure the amount of MWCNTs is 3 wt%. In another embodiment, of the present disclosure the amount of MWCNTs is 1wt % Typically, the purity of the MWCNTs used in the polymeric blend composite of the present disclosure is greater than 90 %, which corresponds to ID/IG =1.10 (ID refers to the intensity of the disordered D-band and IG refers to the intensity of the ordered G-band).
In one embodiment of the present disclosure, MWCNT used is Nanocyl NC 7000 having average diameter 9.5 x10-9 m, average length 1.5 µm, carbon purity 90%, transition metal oxide <1%, surface area 250-300 m2/g and volume resistivity 10-4O.cm .
In an exemplary embodiment of the present disclosure, the polymeric composite of the present disclosure comprises PEK and ABPBI in the ratio of 80/20 and 3 wt% MWCNTs.
The polymeric blend composite of the present disclosure is characterized by having an electrical conductivity greater than 10-12 S/cm, and a storage modulus in the range of 2300 MPa to 3000 MPa at temperature in the range of 50-180 oC and of 230 MPa to 450 MPa at a temperature in the range of 200 oC to 300 oC. The electrical conductivity of the blend composition in the absence of MWCNT (0 wt%) is 10-12 S/cm which is not desirable to process for making the articles. In an embodiment, the electrical conductivity of the blend composition is 10-9 S/cm when 3 wt% MWCNTs are reinforced in the composition. In another embodiment, the electrical conductivity of the blend composition is 10-5 S/cm when 4 wt% MWCNTs are reinforced in the composition. In yet another embodiment, the electrical conductivity of the blend composition is 10-4 S/cm when 5 wt% MWCNTs are reinforced in the composition.
In another aspect of the present disclosure, there is provided a process for preparing a polymeric blend composite comprising PEK, ABPBI, and MWCNTs. The process comprises pre-treatment of the MWCNTs to obtain the pre-treated MWCNTs. PEK, ABPBI, and the pre-treated MWCNTs are then mixed to obtain a processable blend. The so obtained blend is extruded to obtain the polymeric blend composite of the present disclosure.
MWCNTs tend to agglomerate, making it difficult to control the dispersion of the MWCNTs in the polymer blend composite. It is well known that without dispersion, the blend properties are not significantly improved. Therefore, the MWCNTs used in the polymeric blend composite of the present disclosure are pre-treated by ultrasonication to overcome the problem of agglomeration. The MWCNTs, when dispersed in the polymeric blends, show high rigidity at higher temperatures when properly integrated into the polymeric blend to form a composite structure, as the degree of entanglement and the linearity of the MWCNTs also impact the performance of the polymeric blend composite.
In accordance with the present disclosure, the MWCNTs are pre-treated by initially dispersing it in de-ionized water by ultrasonication. Ultrasonicator generates sound waves of high frequencies in the range of 15 to 25 kilohertz (kHz). The sound waves generated, subsequently create ‘bubbles’, which agitate the MWCNTs present in the ultrasonication chamber. The MWCNTs are typically ultrasonicated for a time period in the range of 10 to 60 minutes at ambient temperatures. Subjecting the MWCNTs to ultrasonication reduces the cluster formation (agglomeration) and provides uniformly dispersed MWCNTs. The so obtained uniformly dispersed MWCNTs is dried at a temperature in the range of 80 °C to 120 °C for a time period in the range of 1hour to 24 hours under vacuum 500 mm of Hg, to obtain the pre-treated MWCNTs. The pre-treated MWCNTs are used in the preparation of the polymeric blend composite.
In an embodiment, a pre-determined amount of powdered PEK and ABPBI are dry mixed with the pre-treated MWCNTs, to obtain a mixture. The mixing can be carried out using any mixer, such as a high speed mixer.
In accordance with the embodiments of the present disclosure, the ratio of PEK to ABPBI can be in the range of 60/40 (wt/wt) to 95/5 (wt/wt). In one embodiment, the ratio of PEK to ABPBI is 80/20 (wt/wt). The amount of MWCNTs added to PEK/ABPBI dry blend is in the range of 0.5 wt% to 5 wt% of the total weight of the polymeric blend composition. The blend mixture is further extruded to obtain strands of the polymeric blend composites of the present disclosure. The extrusion is carried out in a twin screw extruder which typically provides a high shear rate.

Extrusion of PEK/ABPBI+MWCNTs composites using a twin screw extruder tends to break or not allow formation of agglomeration of nanomaterials in the composites due to applied high shear.
The speed of extruder screws can be in the range of 350 rpm to 400 rpm. The extrusion can be carried out at a temperature in the range of 320 °C to 400 °C. The process of extrusion comprises feed zone, compression zone, metering zone, and die. Further, temperature of feed zone can be typically in the range of 320 °C to 340 °C, compression zone temperature can be in the range of 340 °C to 375 °C, and metering zone temperature can be in the range of 375 °C to 400 °C, and die temperature can be in the range of 390 °C to 400 °C. The length to diameter (L/D) ratio of the extruder can be in the range of 25 to 35. In one embodiment, the L/D ratio of the extruder is 30.
The polymeric blend composite can be further processed to produce granules. In an embodiment, the extruded strands of the polymeric blend composite can be cooled in air and pelletized to obtain granules, which can then be dried in an oven at temperature in the range of 150 °C to 200 °C, generally above the glass transition temperature of PEK (Tg~152 °C) for a time period of 1 to 5 hours to obtain dried pellets.
Injection Molding can be carried out in an injection molding machine at a temperature in the range of 350 °C to 400 °C.
The polymeric blend composites containing MWCNTs obtained by the process of the present disclosure exhibit high electrical conductivity and improved storage modulus as compared to the polymeric blends comprising PEK and ABPBI.
The polymeric blend composite of the present disclosure can find applications as connectors, thermal interface materials, heat sinks, electronics packaging, self-regulating heaters, PTC resistors, in transport industry especially in aerospace structures, which require a reduction in weight and fuel consumption. These composites can also be used in aeronautical structural components like wing panels, horizontal and vertical stabilizers and some elements of the fuselage. The applications of the polymeric blend composite, thus formed is not restricted its use only to the aforestated applications, but can find in applications in various other sectors where high performance and high temperature resistant materials are required.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further described in light of the following experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. The following experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale.
Experimental Details
Experiment 1: Preparation of PEK/ABPBI blends (PEK/ABPBI 80/20 wt/wt ratio) and with multi-walled carbon nanotubes in accordance with the present disclosure
Step-I: Pre-treatment of MWCNTs
The MWCNTs used in the experiments were Nanocyl NC 7000. MWCNTs Nanocyl NC 7000 was procured from Nanocyl Inc. Sambreville, Belgium.
185 grams of MWCNTs were mixed with 3900 ml of de-ionized water and ultrasonicated (Ultrasonicator ANM Alliance) at a frequency of 20 kilohertz (kHz) for a time period of 20 minutes. After ultrasonication, uniformly dispersed MWCNTs were obtained. The so obtained uniformly dispersed MWCNTs were dried at 80 °C. 182 grams pre-treated MWCNTs were obtained.
Step-II: General process of Preparation of the PEK/ABPBI/MWCNTs polymeric blend composite
532 grams of PEK powder, 133 grams of ABPBI powder (in ratio 80:20), and 35 grams (5wt%) of pre-treated MWCNTs as obtained in Step-I were mixed in a high speed mixer for 10 minutes. The resultant mixture was extruded using a twin screw extruder (W&P Cooperson ZSK 26, L/D ratio 30) at 400 rpm with barrel zones temperatures of 320-400 °C, and die temperature of 390 to 400 °C to obtain the polymeric blend composite in the form of strands, which were air-cooled and further pelletized (using Glaves Corporation pelletizer), followed by drying at 180 °C for 2-3 hours.
The pellets were injection molded (using Arburg All Rounder 320C injection molding machine) at 1400 bar injection pressure and 1200 bar holding pressure and dosage volume of 25 cc and injection flow of 35cc/s to obtain molded samples.
DMTA was measured using TA DMA Q800 in dual cantilever mode as a function of temperature at 1 Hz frequency. DMA sample dimensions were 63.5 x 12.7 x 3.24 mm. HDT was measured using Instron-Ceast, Italy HV-500 HDT/Vicat system and electrical conductivity was measured on sample dimensions 12.7 x 12.7 x 3.24 mm and HDT was measured at 0.25 mm deflection in edgewise position. Electrical conductivity was measured using Broadband Dielectric Spectrometer, Novocontrol, Germany Model Concept 80 using sample dimensions of 12.7 x 12.7 x 3.24 mm, with specimens coated on both surfaces with conductive silver paste to minimize surface resistance. The result obtained is given in Table 1-2 and Figures 1-3.
Experiment 2
Similar procedure as given in step II of experiment 1 was followed, by mixing, extruding and injection molding using 0 wt% MWCNTs to obtain injection molded specimens of the neat polymeric blend composite (sample code: 100P80A20T0 as provided in Table 1) for DMA, electrical conductivity and HDT. The electrical conductivity of this composition is >10-12S/cm.
Experiment 3
Similar procedure as given in experiment 1 was followed by mixing, extruding and injection molding using 1 wt% MWCNTs to obtain injection molded specimens of polymeric blend composite (Sample code: 99P80A20T1 as provided in Table 1) for DMA, electrical conductivity and HDT, giving The electrical conductivity of this composition is 10-12S/cm .
Experiment 4
Similar procedure as given in experiment 1 was followed by mixing, extruding and injection molding using 3 wt% MWCNTs to obtain injection molded specimens of polymeric blend composite (Sample code: 97P80A20T3 as provided in Table 1) ) for DMA, electrical conductivity and HDT. The electrical conductivity of this composition is 10-9 S/cm.
Experiment 5
Similar procedure as given in experiment 1 was followed by mixing, extruding and injection molding 4 wt% MWCNTs to obtain injection molded specimens of polymeric blend composite (Sample code: 96P80A20T4 as provided in Table 1) for DMA, electrical conductivity and HDT. The electrical conductivity of this composition is 10-5 S/cm.
Figure 1 (a)illustrates a graphical representation of AC electrical conductivity versus frequency for PEK/ABPBI+MWCNTs polymeric blend composite, Figure 1 (b) illustrates DC electrical conductivity with respect to various concentration of MWCNTs (wt %) used and Figure 1 (c) illustrates scaling law of DC electrical conductivity with various concentration of MWCNTs (wt %) used in the polymeric blend composite.
Experiment 6
Similar procedure as given in experiment 1 was followed except by mixing, extruding and injection molding PEK with 0 wt% MWCNTs to obtain injection molded specimens of polymeric blend composite. (Sample Code: P100T0 as provided in Table 1) for DMA, electrical conductivity and HDT. The electrical conductivity of this composition is 10-12 S/cm.
Experiment 7
Similar procedure as given in experiment 1 was followed except by mixing, extruding and injection molding PEK with 1 wt% MWCNTs to obtain injection molded specimens of polymeric blend composite. (Sample Code: P99T1 as provided in Table 1) for DMA, electrical conductivity and HDT. The electrical conductivity of this composition is 10-12 S/cm.
Experiment 8
Similar procedure as given in experiment 1 was followed except by mixing, extruding and injection molding PEK with 3 wt% MWCNTs to obtain injection molded specimens of polymeric blend composite. (Sample Code: P97T3 as provided in Table 1) for DMA, electrical conductivity and HDT. The electrical conductivity of this composition is 10-12 S/cm.
Experiment 9
Similar procedure as given in experiment 1 was followed except by mixing, extruding and injection molding PEK with 4 wt% MWCNTs to obtain injection molded specimens of polymeric blend composite. (Sample Code: P96T4 as provided in Table 1) for DMA, electrical conductivity and HDT. The electrical conductivity of this composition is 10-9 S/cm.
Experiment 10
Similar procedure as given in experiment 1 was followed except by mixing, extruding and injection molding PEK with 5 wt% MWCNTs to obtain injection molded specimens of polymeric blend composite. (Sample Code: P95T5 as provided in Table 1) for DMA, electrical conductivity and HDT. The electrical conductivity of this composition is 10-5 S/cm.
Figure 2a illustrates a graphical representation of AC electrical conductivity versus frequency for neat PEK with different mass percentages of MWCNTs, Figure 2 (b) illustrates DC electrical conductivity with respect to various concentration of MWCNTs (wt %) used in neat PEK; and Figure 2 (c) illustrates scaling law of DC electrical conductivity versus various concentration of MWCNTs (wt%) used in neat PEK.

Table 1: HDT and Electrically Conductivity of blends of PEK/ABPBI (80/20) (wt/wt) and PEK with MWCNTs
Experiment No. Sample Code PEK/ABPBI Polymer Blend (wt/wt) Nanocyl NC 7000 MWCNTs HDT AC Electrical Conductivity at 10 Hz Surface Resistivity Nature of the Composite
wt% °C S/cm O
1 95P80A20T5 (80/20) 5 184 10-4 103 Conductive
2 100P80A20T0 (80/20) 0 168 >10-12 1010 Anti-Static
3 99P80A20T1 (80/20) 1 170 10-12 1010 Anti-Static
4 97P80A20T3 (80/20) 3 196 10-9 108 Static Dissipative
5 96P80A20T4 (80/20) 4 198 10-5 105 Conductive

6 P100T0 (100/0) 0 168 >10-12 1010 Anti-Static
7 P99T1 (100/0) 1 170 10-12 1010 Anti-Static
8 P97T3 (100/0) 3 176 10-12 1010 Anti-Static
9 P96T4 (100/0) 4 177 10-9 108 Static Dissipative
10 P95T5 (100/0) 5 179 10-5 104 Conductive

The polymeric blend composite PEK/ABPBI+MWCNTs of the present disclosure exhibits improved and significantly increased electrical conductivity in the range of 0.5wt% to 5wt% as compared to PEK/ABPBI blends without MWCNTs, which is given in Table 1.
The polymeric blend composites of the present disclosure, the neat blend, and a polymeric blend comprising 0 - 5 wt% MWCNTs were tested for storage modulus. Storage Modulus was obtained using TA System DMA equipment in the temperature range of 30 0C to 350 0C. The method used for testing was ASTM D 7028 at Frequency was set at 1 Hertz (Hz). Amplitude was set at 50 µm. The results obtained are summarized in Table-2.
Figure 3 represents a graph illustrating the storage modulus of the polymeric blend composite of PEK and ABPBI (80/20wt/wt) and neat PEK versus varying concentration of MWCNTs at different temperatures (200 °C, 250 °C, and 300 °C) in accordance with the present disclosure
Table 2 Storage Modulus of PEK and PEK/ABPBI (80/20) (wt/wt) blends as a function of Temperature for MWCNTs concentrations 0-5 wt%
Conditions: Fixture: Dual-Cantilever, Frequency = 1 Hz, Amplitude = 50 µm, ASTM D 7028 Sample Dimensions: 63.5 mm x 12.7 mm x 3.24 mm (as per ASTM D 256)
Sample Code Tg by tan d Storage Modulus (E’) at different temperatures (MPa)
°C 50°C 140°C 150°C 180°C 200°C 250°C 300°C
PEK+MWCNTs
P100T0 171 2305 2241 2195 618 412 234 230
P99T1 173 2356 2300 2254 628 387 305 234
P97T3 173 2482 2354 2301 696 372 302 235
P96T4 174 2842 2522 2443 706 368 286 240
P95T5 174 2850 2842 2810 1069 562 362 245
Sample Code Tg by tan d Storage Modulus (E’) at different temperatures (MPa)
PEK/ABPBI (80/20) (wt/wt) + MWCNTs °C 50°C 140°C 150°C 180°C 200°C 250°C 300°C
100P80A20T0 174 2360 2259 2321 1319 426 234 232
99P80A20T1 174 2538 2377 2496 1274 431 344 295
97P80A20T3 174 2750 2575 2544 1583 749 469 359
96P80A20T4 175 2872 2661 2630 1741 743 457 368
95P80A20T5 175 2892 2681 2650 1761 763 477 388
It is observed from the Figure 3 that the high temperature storage modulus of PEK/ABPBI+MWCNTs blend composites is 25% -50% higher than high temperature storage modulus of PEK+MWCNTs composites.
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of polymeric blend composites having, high electrical conductivity, and improved storage modulus.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results. While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Variations or modifications to the formulation of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications are well within the spirit of this invention.
The numerical values given for various physical parameters, dimensions, and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention unless there is a statement in the specification to the contrary.
While considerable emphasis has been placed herein on the specific features of the preferred embodiment, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiment without departing from the principles of the disclosure. These and other changes in the preferred embodiment of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.