Claims:We Claims:
1. PJFs, PPFs, glass fiber and carbon fiber reinforced epoxy hybrid composites is designed to fabricate by managing the locally available eco-friendly cellulosic fibers as useful product development.
i. Management of locally available novel fibers which are eco-friendly
ii. New chemical surface treatment
iii. Higher strength and easy to manufacture
iv. Both lower maintenance and fabrication cost
2. The process as claimed in claim 1, wherein the step (i) the novel abundantly available fibers such as PJFs and PPFs can be utilized as reinforcement material for any type of polymer material.
3. The process as claimed in claim 1, wherein the step (ii) new chemical surface treatment has been applied for the extraction of prosopis juliflora bark fibers and phoenix pusilla leaf fibers
4. The process as claimed in claim 1, wherein the step (iii) the handling of PJFs, PPFs, glass fiber, carbon fiber and epoxy polymer resin is easy which leads to fabrication of new hybrid composite materials.
5. The process as claimed in claim 1, wherein the step (iv) the fabrication and maintenance cost only acquires the price of Glass fiber, carbon fiber and epoxy resin and there is no cost for PJFs and PPFs, due to it readily available from locally available plants.
6. The process as claimed in claim 2, 3, 4, and 5, wherein the fabricated hybrid polymer composites have higher strength, lower weight, easy to manufacture, lower fabrication, maintenance cost, and higher thermal stability.
7. The process as claimed in claim 1, wherein it is applicable to different medium load structural applications in the fields of household appliances, sports goods, automobile sectors, and other useful products.

Date: 04th January 2020.
Mr. Madhu P
Dr. Sanjay M R
Dr. Pradeep S
Dr. Mohit H
Dr. Yogesha B
Prof. Dr.-Ing. Habil. Suchart Siengchin
, Description:1. Background of the invention:
The ever increasing deforestation around the globe has resulted in rapid declination of traditional structural materials like wood and metals and has limited their availability in the universe. Also, it has had some adverse effects on environment and has made the researchers, engineers and scientists to look out for new structural materials with favorable characteristics. These situations have effected in the birth of composite materials which signifies that the most advanced technological advancements has undergone in the area of material science and engineering. With the beginning of use of fiber reinforced polymer composites during the year 1960, these composites were utilized by many industries such as civil engineering sectors, military, marine and aerospace industries to manufacture their structural components. Furthermore, their potentiality in reducing weight and excellent product performance has generated interest among many engineering and structural industries to these materials to manufacture their components.
A composite material is normally referred to as a material arrangement composed of two macroscopically identifiable materials functioning towards achieving superior results. These two material systems are generally phrased as continuous and discontinuous phases. The continuous phase is also called as matrix phase, while the discontinuous phase is termed as reinforcement phase. Among these, the discontinuous phase is generally a tough and stiffer phase compared to matrix phase. The reinforcing materials could appear in the form of flakes, particles and fibers. The matrix material could be used in the form of metallic, polymeric and ceramic.
The composite materials can be categorized depending on the type of reinforcing material or by the type of matrix material used. Reinforcement phase is available in two major forms: fibers (including whiskers) and particles (having different shapes and sizes). Consequently, the two major classes of composites are fiber reinforced composite group (FRCs) and particle reinforced composite group (PRCs). Next, according to matrix phase, composites are grouped into three classes: polymers, ceramics and metals (along with their alloys). The composites using these matrices are phrased as ceramic matrix composites (CMCs), metal matrix composites (MMCs) and polymer matrix composites (PMCs). Other way of classifying the composites include laminar composites (generally called as laminates or laminated composites). Laminates are usually composed of two or more layers of planar composites with each of their ply belonging to either similar or different material. Laminated composite structures tend to be much strong and stiff, and generally recommended to be used in lightweight structural applications.
Polymeric matrix composites due their high strength, cheap availability and simple manufacturing principles have been the most commonly used class of materials preferred by many industries for developing their products. PMCs are usually composed of a polymer reinforced with thin diameter fibers (natural or synthetic). Polymers in general, are categorized into two types namely thermoset and thermoplastic polymers.
Fibers in PMCs are usually called as fiber reinforced polymer composites (FRPCs) can either be composed of synthetic/man-made fibers or natural fibers and are manufactured with or without the appliance of filler materials. Synthetic fibers are the fibers made artificially by man using some minerals and are termed as synthetic fiber composites (SFCs). Synthetic fibers are acknowledged as one of the important reinforcing material systems in composites particularly in the field of aerospace, automotive and energy conversion sectors where thermal, mechanical and chemical resistivity properties are important criteria’s to be satisfied. The general kind of synthetic fibers used are carbon, aramid, glass, alumina silicon carbide and polyethylene. The present research concentrates on the utilization of E-glass and carbon as synthetic form of reinforcements.
While synthetic fibers are the man-made fibers, the natural fibers as the name implies are the fibers available naturally on the earth and can be called as a God’s gift to human race. The word “natural” refers to the substance that is available naturally, while the term “fiber” resembles to a thread or hair like arrangement having elevated aspect ratio. As reinforcement phase in polymeric composites, natural fibers may be used either in fibrous or non- fibrous from and are better known as natural fiber composites (NFCs). NFCs are mainly categorized as; cellulosic or plant fibers, animal fibers and mineral fibers.
Plant or cellulosic fibers are the most preferred natural fibers because of their various eco-friendly properties and their capability to minimize world global energy crisis. The natural fibers are accessible in various forms such as seed fibers (milkweed, kapok), grass fibers (bagasse, bamboo), leaf fibers (abaca, banana, curaua, sisal), bast fibers (jute, hemp, ramie, kenaf), fruit fibers (oil palm, coir), stalks (wheat, rice, maize) and wood fibers (hardwood and softwood). The advantages that had made these fibers to be employed as reinforcements in polymeric composites include less density, low cost, better recyclability, easy and availability in abundance, biodegradability and good processing flexibility. They find application in production of following items; beams, bridges, roof panels, tennis rackets, bicycle frames, automotive parts, consumer goods, tables, chairs, pipes and rotor blades.
Although the environmental friendly advantages of natural fibers have made natural fibers to be used more frequently than synthetic fibers as reinforcement materials in polymeric matrix composite systems, these fibers have got some drawbacks which had limited their use in some polymer industries. The main drawbacks of these fibers, particularly when they are used in untreated form in polymer matrices are,
a. Poor Interfacial bonding: The chemical structure of cellulosic fibers has made them more polar and hydrophilic in nature. The main reason for their hydrophilicity is because of the presence of some amorphous materials such as hemicellulose, lignin and pectins that contain hydroxyl (OH) and carboxylic acid groups which would result in more sorption of water. But, the matrices used in composites tend to be non-polar and hydrophobic in nature and when some incompatible polar cellulose fibers are incorporated with these non-polar matrices would result in poor adhesion. As, a result it may result in composite material system with poor mechanical properties.
b. Limited thermal stability: Unlike synthetic fibers, most of the cellulosic fibers begin to degrade thermally around the temperature 180-2000 C. This makes them to be restricted to be used in only certain composites operating at low temperature applications.
c. High moisture absorption: Another main drawback of these lignocellulosic fibers is their high moisture absorption behaviour guiding to fiber swelling and dimensional alteration in composite material systems. Fiber swelling indirectly affects in poor adhesion behaviour property among fibers and matrix resulting in poor mechanical properties of composite material systems. The hydrophilic behaviour of these cellulose fibers consequences in the discharge of water vapor from composite materials during elevated temperature compounding thus leading to porous structure. This porous structure may result in untimely failure of the composite systems during fiber surface loading.
As discussed above, these drawbacks of natural fibers have made the researchers around the globe to look for the techniques to overcome these issues. With respect to this researchers have came with a solution of enhancing the interfacial adhesion behaviour among hydrophilic fibers and hydrophobic matrix by transforming the fibers or the matrix or both by using various chemical and physical methods available. Fiber treatment or modification technique is a biological or chemical method carried out to remove undesirable constituents from fibers, separating individual fibers from fiber bundle, to chemically transform the structure of fibers and to eliminate hydrophilicity. The fiber treatment methods commonly used are pre-treatment method, dispersing agent method, compatibilizer method and coupling agent method. Matrix modification method involves adding some chemical coupling agents or compatibilizer to polymer matrices to enhance polymer reactivity and reinforcing fibers wetting property.
The most widely used fiber modification technique is coupling agent method. This method helps in improving interfacial adhesion properties among the fibers and matrices, as well as reduces the water uptake of fibers and aids in fiber dispersion. Presently, more than thirty coupling agents have been employed in the manufacturing and investigation of NFCs. The most admired treatment techniques that are being used are alkaline, benzoylation, permanganate, stearic acid, silane, sodium chlorite, acetylation, fungal, maleated coupling agents, isocyanates and acrylation grafting techniques.

Although natural fibers have got eco-friendly advantages to be implemented in some automobile, household and construction applications, they alone cannot exhibit enough mechanical properties to be exploited in some important structural applications. The limited use of these fibers in structural applications is also attributed to their poor moisture absorption resistance as compared with manmade synthetic fiber composites. In this context, there is growing attention in the developing hybrid fiber composites constituting of synthetic and natural fibers which is enhancing the optimal use of natural resources and understanding the physico- mechanical properties of composites prepared from natural and synthetic fibers. These hybrid composite materials are becoming more attractive structural materials nowadays due to their reduced production cost and improved mechanical properties. The term “hybrid” in hybrid composites refers to the material structure comprising of diverse mixture of matrices coupled with more than one reinforcing and filler materials. The main advantage of hybrid composite material systems is that, as it is composed of more than one fiber, if one fiber lags in some properties it will be compensated by the other fiber and also helps in better cost balance as well as by proper material design considerations performance of the composites will be enhanced.
The focus of this present research investigation is to develop a novel polymeric based natural/ synthetic hybrid fiber reinforced composites. The bark fibers of Prosopis juliflora plant and leaf fibers of Phoenix pusilla plant have been selected as natural fibers, while E-glass and carbon fabrics are selected as synthetic reinforcements.
No articles regarding the development of hybrid polymer composites reinforced with Prosopis juliflora bark fibers and Phoenix pusilla leaf fibers with synthetic glass and carbon fibers could be observed in the open literature.

2. Description of the invention:
2.1. Extraction of prosopis juliflora bark fibers (PJFs)
The bark fibers from Prosopis juliflora (PJ) plant were collected from M. Kallupatti, Madurai district, Tamil Nadu, India. Initially, the raw PJFs were rinsed in water to allow them for microbial degradation for a period of about 2weeks so that both inner and outer layers became soft. Later, the outer layer was disposed off from the inner layer and required fibers from PJFs bark inner layers were collected by traditional combing method. Later, these extracted fibers were dried for 1 week in atmospheric air for maximum removal of moisture for further analysis. Further, the PPFs were treated with alkali using a 6% (w/v) NaOH solution for 45 min of soaking time. After treatment, they are treated in an oven for 3 hrs maintained at 700 C.

2.2. Extraction of phoenix pusilla leaf fibers (PPFs)
The P. pusilla plant leaves were collected from a village in Virudhanagar district near Madurai road, Tamil Nadu, Southern India. The extracted fibres from the matured and fallen leaves of P. pusilla plant were initially soaked in water for three weeks, later the top and bottom layers from the leaf fibres were separated using a smooth brush. Then these separated fibres were thoroughly cleaned using purified water and dried in the sunlight for 7 days. The dried fibres were placed in an oven for a day to eradicate the residual moisture content. Further, the PPFs were treated with alkali using a 6% (w/v) NaOH solution for 45 min of soaking time. Later, the treated PPFs are washed with deionized water, followed by the addition of a few drops of 0.1 N hydrochloric acid to remove excess impurities.

2.3. Fabrication of PJFs/ PPFs/ E-glass/ Carbon fiber reinforced hybrid epoxy composites
The composite laminates were fabricated using manual hand layup method by varying the number and sequence of PJFs/E-Glass/Carbon fabric layers and PPFs/E-Glass/Carbon fabric layers under various stacking sequences. The both combination fabrics were cut into the dimensions of 300×300 mm2 for the preparation of composite laminates. Each composite laminate under the both combinations consisted of four 3 plies and six 5 plies of fabric layers and were manufactured by varying stacking sequences. Initially, mold release sheet was placed on the bottom surface of the mold for easy removal of composite laminates. The inner mold wall surface was sprayed with a mold release agent for easier removal of composite laminate prepared. The epoxy resin and hardener mixture was thoroughly mixed in a container and was then poured on the prepared mold. Then the PJFs, PPFs, E-glass and carbon fabrics were kept as per stacking sequence and then epoxy-hardener mixture is applied after placing each layer of fibers, equally distributed by roller followed by hand lay-up. After 5 mins of rolling a mold release sheet was positioned over the top of mold and before mixture gets hardened, a wooden board of mold size was kept on the top of the mold with dead weights for a period of 2 days. After 2 days, the laminates were taken out from the mold and were cut as per standard ASTM methods for mechanical testing.
Laminate stacking sequence of PJFs/E-glass/Carbon fibers
Laminates Stacking sequence
MPJ1E G+PJF+G
MPJ2E C+PJF+C
MPJ3E G+G+PJF+G+G
MPJ4E C+C+PJF+C+C
MPJ5E C+G+PJF+G+C

Laminate stacking sequence of PPFs/E-glass/Carbon fibers
Laminates Stacking sequence
MPP1E G+PPF+G
MPP2E C+PPF+C
MPP3E G+G+PPF+G+G
MPP4E C+C+PPF+C+C
MPP5E C+G+PPF+G+C

2.4. Hybrid composite testing
The density of the composite laminates was evaluated using water immersion technique, where pure condensed water was used for the experiment. For each sample investigated, six measures were carried out and average value was noted down. By using ASTM D2734-94 method, voids in the composites were determined in the present investigation. The tensile strength and modulus of the hybrid composite laminates were tested according to ASTM D 3039 (254×25.4×3 mm) on the straight flat specimens using Computerized Universal Testing Machine (Kalpak UTM, Model: KIC-2-1000-C) with 100 KN load cell. The experiments were carried out on six identical test specimens with a constant strain rate of 2.5 mm/min at a room temperature of 25 0C. The flexural strength and modulus properties of the prepared composite laminates were determined using 3-point bending method using same UTM utilizing flexural test fixtures according to ASTM D 790-07 (90×10×3 mm) method with load cell of 10 KN and loading rate of 2.0 mm/min. The flexural specimens were gripped between two jaws at a span length of 70 mm with load being functioned exactly at centre. The load was applied until gauge length of the sample increased and the sample broke. The impact test samples are prepared and tested according to the standard ASTM D 256-06 (63×12.7×3 mm). The Izod test was performed on six samples using pendulum impact tester. The amount of energy absorbed by the sample before it got fractured was recorded in terms of J/m and was used to measure ductility and toughness. The experiment was conducted at a room temperature of 25 0C. The Inter-laminar shear strength (ILSS) test was performed in the Computerized Universal Testing Machine (Kalpak UTM, Model: KIC-2-1000-C) using inter-laminar test fixtures. Six ILSS samples were made according to standard ASTM D 2344 (60×10×3 mm) method. The ILSS samples were gripped between two jaw supports at a span length distance of 40 mm and were loaded under 3 - point bending condition maintained at a loading rate of 1.5 mm/min. The span to depth ratio of 4:1 (L/t) was chosen for test. Further, the ILSS samples were subjected under bending and transverse shear stresses with the loading cylinder exerting downward force. The micro-hardness property of the prepared composite laminate was scrutinized using a Matsuzawa micro-hardness tester (Model: MMT-X7A) according to ASTM E384 standard. The tensile samples were utilized for the test in the current research work. The micro-hardness test was carried out using a square based right pyramid shaped diamond indenter of 1000 HV having an apical angle of 1360, under a load of around 100gf and dwell time period of 15 sec. The Vickers hardness was directly recorded from the digital tester.
Complete specification of the PJFs/ E-glass/ Carbon fiber reinforced hybrid epoxy composites
Laminates Density
(g/cc) Volume fraction of voids
(%) Tensile strength
(Mpa) Flexural strength (Mpa) Impact test (J/m) Interlaminar shear strength (Mpa) Micro Hardness (HV)
MPJ1E 1.0552 0.472 82.845 195.838 613.4 7.094 17.76
MPJ2E 1.0234 0.195 114.653 211.244 639.1 8.964 20.27
MPJ3E 1.2623 0.363 246.93 300.693 1101.7 17.366 24.16
MPJ4E 1.1677 0.298 383.237 346.272 1186.6 20.141 39.74
MPJ5E 1.2149 0.216 287.82 328.58 1172.8 19.282 33.57

Complete specification of the PPFs/ E-glass/ Carbon fiber reinforced hybrid epoxy composites
Laminates Density
(g/cc) Volume fraction of voids
(%) Tensile strength
(Mpa) Flexural strength (Mpa) Impact test (J/m) Interlaminar shear strength (Mpa) Micro Hardness (HV)
MPP1E 0.7312 0.544 77.68 164.226 588.3 5.428 16.97
MPP2E 0.7086 0.281 103.904 207.186 615.4 6.249 19.39
MPP3E 1.0139 0.461 217.34 263.734 1082.2 14.878 23.57
MPP4E 0.9230 0.517 338.96 317.47 1170.2 18.814 39.13
MPP5E 0.9352 0.309 247.83 298.46 1154.4 16.995 32.98

Development of new material
1. Successful fabrication of multilayered hybrid composite by reinforcing two low cost, light weight, eco-friendly natural fibers (prosopis juliflora bark fibers and phoenix pusilla leaf fibers) with glass and carbon fiber, using a epoxy matrix using hand lay-up technique.
2. The prepared hybrid composites can be used in the production of some medium load structural applications such as car dash boards, bicycle frames, snowboards, laptop stands and helmets.

Objectives of the invention:
The objective of the invention is to provide a new material reinforced with prosopis juliflora bark fibers, phoenix pusilla leaf fibers, glass fiber, carbon fiber in epoxy matrix hybrid composites at cheaper cost, light weight, and higher mechanical properties.
Advantages:
1. High strength
2. Higher durability
3. Higher mechanical properties
4. Lower cost of fabrication
5. Higher thermal stability
6. Withstand at higher loads