Comparative Studies on the Mechanical,Degradation and Interfacial Properties between Jute and E-Glass Fiber-Reinforced PET Composites

Jute fiber mat (hessian cloth) reinforced PET-based composites (50% fiber by weight) and E-glass fiber matreinforced PET based composites (50% fiber by weight) were fabricated by compression molding and the mechanical properties tensile strength (TS), tensile modulus (TM), elongation at break (%), bending strength (BS), bending modulus (BM), impact strength (IS) and hardness (Shore-A) of the composites were evaluated and compared. The interfacial properties of the both composites were also compared. Water uptake test and soil degradation test were also investigated.     

玻纤增强PP热塑性片材的制备及力学性能研究

采用熔融浸渍法制备了玻璃纤维毡增强聚丙烯（PP）热塑性复合片材；通过在PP中加入复合改性PP改善了基体与增强纤维间的相容性；考察了相容剂、PP种类及玻纤毡种类对复合片材的影响。结果表明，相容剂的加入可使复合片材的拉伸强度提高29％、拉伸模量提高23％、弯曲强度提高42％、弯曲模量提高25％；高熔体质量流动速率PP可使片材的弯曲与冲击性能进一步改善。连续玻纤毡和长玻纤毡增强PP复合片材，前者综合力学性能良好，而后者则冲击强度较弱、弯曲性能加强。     

挤出-注塑制备黄麻增强PLA复合材料及其性能

通过挤出共混、造粒、注射成型的方式制备了黄麻纤维填充聚乳酸(PLA)复合材料,研究了复合材料的力学性能以及黄麻与PLA之间的微观界面形貌。结果表明:黄麻的加入,并没有很好地改善黄麻/PLA复合材料的拉伸强度和弯曲强度;碱处理后的黄麻与PLA之间的界面性能有所改善;碱处理黄麻的加入,改善了黄麻/PLA复合材料的断裂伸长率与冲击韧性。     

锦葵纤维增强聚丙烯基复合材料力学性能研究

分别制备了锦葵纤维含量为10 %（质量分数,下同）、20 %、30 %、40 %和50 %的锦葵纤维增强增强聚丙烯基复合材料,研究了纤维含量对该复合材料拉伸性能和弯曲性能的影响,并与苎麻纤维增强聚丙烯基复合材料进行了对比。结果表明,随着锦葵纤维含量的增加,锦葵纤维增强聚丙烯基复合材料的拉伸强度和拉伸弹性模量逐渐增加,而弯曲强度和弯曲弹性模量呈现先增大后减小的趋势,当纤维含量为40 %时达最大值;纤维含量均为30 %时,除拉伸弹性模量外,锦葵纤维增强聚丙烯基复合材料的各项指标均低于苎麻纤维增强聚丙烯基复合材料。     

Studies of the Physico-Mechanical,Interfacial, and Degradation Properties of Jute Fabrics/Melamine Composites

Jute fabrics/melamine composites (20% fiber) were prepared by compression molding. Mechanical properties of the composites were evaluated. Mechanical properties of starch-treated jute/melamine composites, including tensile strength (31%), bending strength (29%), tensile modulus (23%), bending modulus (25%), impact strength (113%), and hardness (4%), inproved significantly over the untreated composite. Fracture surfaces of untreated and treated composites were studied by scanning electron microscopy (SEM) and supported poorer fiber matrix adhesion for the untreated composite than that of the treated composite. Water uptake and soil degradation tests of untreated and treated composites were also performed.     

Effect of macromolecular coupling agent on the property of PP/GF composites

Silane‐grafted polypropylene manufactured by a reactive grafting process was used as the coupling agent in polypropylene/glass‐fiber composites to improve the interaction of the interfacial regions. Polypropylene reinforced with 30% by weight of short glass fibers was injection‐molded and the mechanical behaviors were investigated. The results indicate that the mechanical properties (tensile strength, tensile modulus, flexural strength, flexural modulus, and Izod impact strength) of the composite increased remarkably as compared with the noncoupled glass fiber/polypropylene. SEM of the fracture surfaces of the coupled composites shows a good adhesion at the fiber/matrix interface: The fibers are coated with matrix polymer, and a matrix transition region exists near the fibers. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1537–1542, 1999     

Influence of fly ash cenospheres on performance of coir fiber‐reinforced recycled high‐density polyethylene biocomposites

Recycled high‐density polyethylene (RHDPE)/coir fiber (CF)‐reinforced biocomposites were fabricated using melt blending technique in a twin‐screw extruder and the test specimens were prepared in an automatic injection molding machine. Variation in mechanical properties, crystallization behavior, water absorption, and thermal stability with the addition of fly ash cenospheres (FACS) in RHDPE/CF composites were investigated. It was observed that the tensile modulus, flexural strength, flexural modulus, and hardness properties of RHDPE increase with an increase in fiber loading from 10 to 30 wt %. Composites prepared using 30 wt % CF and 1 wt % MA‐g‐HDPE exhibited optimum mechanical performance with an increase in tensile modulus to 217%, flexural strength to 30%, flexural modulus to 97%, and hardness to 27% when compared with the RHDPE matrix. Addition of FACS results in a significant increase in the flexural modulus and hardness of the RHDPE/CF composites. Dynamic mechanical analysis tests of the RHDPE/CF/FACS biocomposites in presence of MA‐g‐HDPE revealed an increase in storage (E′) and loss (E″) modulus with reduction in damping factor (tan δ), confirming a strong influence between the fiber/FACS and MA‐g‐HDPE in the RHDPE matrix. Differential scanning calorimetry, thermogravimetric analysis thermograms also showed improved thermal properties in the composites when compared with RHDPE matrix. The main motivation of this study was to prepare a value added and low‐cost composite material with optimum properties from consumer and industrial wastes as matrix and filler. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42237.     

Poly(lactic acid)–thermoplastic poly(ether)urethane composites synergistically reinforced and toughened with short carbon fibers for three‐dimensional printing

In this study, we prepared short‐carbon‐fiber (CF)‐reinforced poly(lactic acid) (PLA)–thermoplastic polyurethane (TPU) blends by melt blending. The effects of the initial fiber length and content on the morphologies and thermal, rheological, and mechanical properties of the composites were systematically investigated. We found that the mechanical properties of the composites were almost unaffected by the fiber initial length. However, with increasing fiber content, the stiffness and toughness values of the blends were both enhanced because of the formation of a TPU‐mediated CF network. With the incorporation of 20 wt % CFs into the PLA–TPU blends, the tensile strength was increased by 70.7%, the flexural modulus was increased by 184%, and the impact strength was increased by 50.4%. Compared with that of the neat PLA, the impact strength of the CF‐reinforced composites increased up to 1.92 times. For the performance in three‐dimensional printing, excellent mechanical properties and a good‐quality appearance were simultaneously obtained when we printed the composites with a thin layer thickness. Our results provide insight into the relationship among the CFs, phase structure, and performance, as we achieved a good stiffness–toughness balance in the PLA–TPU–CF ternary composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46483.     

Ionic Liquid Approach Toward Manufacture and Full Recycling of All‐Cellulose Composites

All‐cellulose composites (ACCs) are prepared from high‐strength rayon fibers and cellulose pulp. The procedure comprises the use of a pulp cellulose solution in the ionic liquid (IL) 1‐ethyl‐3‐methyl imidazolium acetate ([EMIM][OAc]) as a precursor for the matrix component. High‐strength rayon fibers/fabrics are embedded in this solution of cellulose in the IL followed by removal of the IL. Different concentrations of cellulose in the IL are investigated and the mechanical properties of the final ACCs are determined via tensile, bending, and impact testing. ACCs prepared in this study show mechanical properties comparable to thermoplastic glass fiber‐reinforced plastics. Apart from being bio‐based, they possess several advantages such as biodegradability and full recyclability. The recycling of ACCs is successfully demonstrated in several cycles by using the recycled cellulose for subsequent matrix preparation.     

Short glass fiber reinforced ABS and ABS/PA6 composites: Processing and characterization

In this study acrylonitrile‐butadiene‐styrene (ABS) terpolymer was reinforced with 3‐aminopropyltrimethoxysilane (APS)‐treated short glass fibers (SGFs). The effects of SGF concentration and extrusion process conditions, such as the screw speed and barrel temperature profile, on the mechanical properties of the composites were examined. Increasing the SGF concentration in the ABS matrix from 10 wt% to 30 wt% resulted in improved tensile strength, tensile modulus and flexural modulus, but drastically lowered the strain‐at‐break and the impact strength. The average fiber length decreased when the concentration of glass fibers increased. The increase in screw speed decreased the average fiber length, and therefore the tensile strength, tensile modulus, flexural modulus, and impact strength were affected negatively and the strain‐at‐break was affected positively. The increase in extrusion temperature decreased the fiber length degradation, and therefore the tensile strength, tensile modulus, flexural modulus, and impact strength increased. At higher temperatures the ABS matrix degraded and the mechanical strength of the composites decreased. To obtain a strong interaction at the interface, polyamide‐6 (PA6) at varying concentrations was introduced into the ABS/30 wt% SGF composite. The incorporation and increasing amount of PA6 in the composites broadened the fiber length distribution (FLD) owing to the low melt viscosity of PA6. Tensile strength, tensile modulus, flexural modulus, and impact strength values increased with an increase in the PA6 content of the ABS/PA6/SGF systems due to the improved adhesion at the interface, which was confirmed by the ratio of tensile strength to flexural strength as an adhesion parameter. These results were also supported by scanning electron micrographs of the ABS/PA6/SGF composites, which exhibited an improved adhesion between the SGFs and the ABS/PA6 matrix. POLYM. COMPOS. 26:745–755, 2005. © 2005 Society of Plastics Engineers     

Studies of different kinds of fiber pretreating on the properties of PLA/sweet sorghum fiber composites

In this article, truly degradable composites were prepared using sweet sorghum fibers which are residue of ethanol fermentation industry as reinforcement and renewable resource‐based biodegradable polyester, poly(L ‐lactide) (PLLA) as matrix, they were fabricated by melt‐blending. The effect of different kinds of pretreatments (dilute sulfuric acid pretreatment, mild alkaline/oxidative pretreatment, steam explosion pretreatment) on mechanical properties of composites were investigated. Besides the composition of untreated and treated fibers as determined by Van soest method, Fourier transformed infrared (FTIR) spectroscopic and scanning electron microscopic (SEM) were also used to study the change of sweet sorghum fibers before and after pretreatments. Mechanical properties testing indicated that tensile strength and impact strength of PLLA/treated fibers were improved except the dilute sulfuric acid pretreated fibers reinforced PLA composite. The mild alkaline/oxidative pretreated fiber reinforced PLA composite showed highest tensile strength of 46.12 MPa and impact strength of 8.02 kJ/m² which was 15.5 and 33% higher than that of the control. The SEM of impact fracture surface and DMTA test were carried out to investigate the interfacial morphology and interfacial adhesion between the fiber and matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

玻纤、粉煤灰增强MC尼龙复合材料的研究

利用铸型尼龙(MC尼龙)静态浇铸的原理，通过阴离子聚合制得了玻纤、粉煤灰增强MC尼龙。研究了不同玻纤和粉煤灰质量分数对复合材料性能的影响。结果表明，用这种方法制得的玻纤、粉煤灰增强MC尼龙的机械性能较普通MC尼龙有较大幅度提高，纤维在基体中的分散性好，与基体的粘接性也相当好；加入30％玻璃纤维和10％粉煤灰可使复合材料的拉伸强度提高13．8％、弯曲强度提高32．8％、弯曲弹性模量提高110％、无缺口冲击韧性提高442％、而硬度提高49．6％。     

Biodegradable composites of poly(butylene succinate‐co‐butylene adipate) reinforced by poly(lactic acid) fibers

Biodegradable composites of poly(butylene succinate‐co‐butylene adipate) (PBSA) reinforced by poly(lactic acid) (PLA) fibers were developed by hot compression and characterized by Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), dynamic mechanical analyzer, and tensile testing. The results show that PBSA and PLA are immiscible, but their interface can be improved by processing conditions. In particular, their interface and the resulting mechanical properties strongly depend on processing temperature. When the temperature is below 120 °C, the bound between PBSA and PLA fiber is weak, which results in lower tensile modulus and strength. When the processing temperature is higher (greater than 160 °C), the relaxation of polymer chain destroyed the molecular orientation microstructure of the PLA fiber, which results in weakening mechanical properties of the fiber then weakening reinforcement function. Both tensile modulus and strength of the composites increased significantly, in particular for the materials reinforced by long fiber. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43530.     

Comparative Studies of Mechanical and Interfacial Properties Between Jute Fiber/PVC and E-Glass Fiber/PVC Composites

Composites (50 wt% fiber) of jute fiber reinforced polyvinyl chloride (PVC) matrix and E-glass fiber reinforced PVC matrix were prepared by compression molding. Mechanical properties such as tensile strength (TS), tensile modulus (TM), bending strength (BS), bending modulus (BM) and impact strength (IS) of both types of composites was evaluated and compared. Values of TS, TM, BS, BM and IS of jute fiber/PVC composites were found to be 45 MPa, 802 MPa, 46 MPa, 850 MPa and 24 kJ/m², respectively. It was observed that TS, TM, BS, BM and IS of E-glass fiber/PVC composites were found to increase by 44, 80, 47, 92 and 37.5%, respectively. Thermal properties of the composites were also carried out, which revealed that thermal stability of E-glass fiber/PVC system was higher. The interfacial adhesion between the fibers (jute and E-glass) and matrix was studied by means of critical fiber length and interfacial shear strength that were measured by single fiber fragmentation test. Fracture sides after flexural testing of both types of the composites were investigated by Scanning Electron Microscopy.     

Pultruded fiber reinforced thermoplastic poly(methyl methacrylate) composites. Part II: Mechanical and thermal properties

A novel process has been developed to manufacture poly(methyl methacrylate) (PMMA) pultruded parts. The mechanical and dynamic mechanical properties, environmental effects, postformability of pultruded composites and properties of various fiber (glass, carbon and Kevlar 49 aramid fiber) reinforced PMMA composites have been studied. Results show that the mechanical and thermal properties (i.e. tensile strength, flexural strength and modulus, impact strength and HDT) increase with fiber content. Kevlar fiber/PMMA composites possess the highest impact strength and HDT, while carbon fiber/PMMA composites show the highest tensile strength, tensile and flexural modulus, and glass fiber/PMMA composites show the highest flexural strength. Experimental tensile strengths of all composites except carbon fiber/PMMA composites follow the rule of mixtures. The deviation of carbon fiber/PMMA composite is due to the fiber breakage during processing. Pultruded glass fiber reinforced PMMA composites exhibit good weather resistance. They can be postformed by thermoforming, and mechanical properties can be improved by postforming. The dynamic shear storage modulus (G′) of pultruded glass fiber reinforced PMMA composites increased with decreasing pulling rate, and G′ was higher than that of pultruded Nylon 6 and polyester composites.     

环氧树脂/短切碳纤维复合材料性能研究

制备出了短切碳纤维增强TDE-85环氧树脂复合材料,研究了碳纤维的含量对复合材料力学性能和耐热性能的影响。结果表明,碳纤维的加入有利于复合材料力学性能和耐热性能的提高,并在碳纤维含量为0.25%时,复合材料的拉伸强度、冲击韧性、弯曲强度和弯曲模量达到最大,分别提高了29.33%、25.31%、30.28%和68.93%。此外,对复合材料的弯曲断裂面进行了微观形貌分析,结果表明一定量的碳纤维可以较好地分散在树脂基体中,同时,碳纤维原丝和树脂基体的界面结合比较弱,主要依赖于两相之间的物理嵌合。     

原位微纤增强复合材料的结构与性能

采用熔融挤出——热拉伸——牵引拉伸制备了HDPE/PA6原位成纤增强复合材料,通过SEM分析了分散相PA6含量对其在基体中的形态及分布的影响;讨论了两种加工方式条件下分散相PA6含量对复合材料拉伸性能和冲击韧性的影响以及加工方式对复合体系力学性能的影响。结果表明：在原位成纤增强复合材料中存在直径为2～5 μm的纤维,当HDPE/PA6质量比为85/15时,微纤直径约为3 μm,此时,与普通共混复合材料相比,原位成纤增强复合材料的拉伸强度提高了6.9%,拉伸模量提高了14.8%,冲击强度提高10.03%。     

Caulis spatholobi residue fiber reinforced biodegradable poly (propylene carbonate) composites: The effect of fiber content on mechanical and morphological properties

Adding caulis spatholobi residue fiber (CSRF) to reinforce biodegradable poly (propylene carbonate) (PPC) as a reinforcement was investigated. The morphology of CSRF before and after continuous steam explosion, the mechanical and morphological properties of PPC/CSRF bio‐composites with different fiber content were investigated using scanning electron microscopy (SEM), mechanical tests and infrared spectroscopy. The tensile strength and modulus, and impact strength of the bio‐composites increased as the content of fiber increased in composites, the elongation at break declined. It was found that a small stay‐segment in the stress–strain curves and pulled‐out fibers on fractured surfaces of the composites. Infrared spectra result showed esterification and formation of hydrogen bonds between the matrix and CSRF. The fractured surface of the composites addressed a promotion of the interfacial interactions. POLYM. COMPOS., 35:208–216, 2014. © 2013 Society of Plastics Engineers     

Development of Silicon Carbide Reinforced Jute Epoxy Composites: Physical,Mechanical and Thermo-mechanical Characterizations

The aim of the present study was to investigate the physical and thermo-mechanical characterization of silicon carbide filled needle punch nonwoven jute fiber reinforced epoxy composites. The composite materials were prepared by mixing different weight percentages (0–15 wt.%) of silicon carbide in needle punch nonwoven jute fiber reinforced epoxy composites by hand-lay-up techniques. The physical and mechanical tests have been performed to find the void content, water absorption, hardness, tensile strength, impact strength, fracture toughness and thermo-mechanical properties of the silicon carbide filled jute epoxy composites. The results indicated that increase in silicon carbide filler from 0 to 15 wt.% in the jute epoxy composites increased the void content by 1.49 %, water absorption by 1.83 %, hardness by 39.47 %, tensile strength by 52.5 %, flexural strength by 48.5 %, and impact strength by 14.5 % but on the other hand, decreased the thermal conductivity by 11.62 %. The result also indicated that jute epoxy composites reinforced with 15 wt.% silicon carbide particulate filler presented the highest storage modulus and loss modulus as compared with the unfilled jute epoxy composite.     

不同增韧剂对PLA/稻壳木塑复合材料力学性能影响

以PLA、稻壳粉为原材料,分别加入玻璃纤维、乙烯-辛烯共聚物(POE)、碳酸钙为增韧剂进行增韧改性,以模压成型的方法制备了PLA/稻壳木塑复合材料,结合力学性能、吸水性能、X射线衍射(XRD)分析和对材料表面的显微观察研究了不同种类及含量的增韧剂对木塑复合材料力学性能的影响。结果表明,在玻璃纤维含量为20%的时候,PLA/稻壳木塑复合材料的增韧效果较好,其洛氏硬度值达68,其拉伸强度达到6.16 MPa,弯曲强度达到15.41 MPa,冲击强度为144.40 kJ/m2,但吸水性能显著提高,约为不添加增韧剂时的1.5倍;在POE含量为20%的时候,PLA/稻壳木塑复合材料吸水性降低效果最为显著,60 h浸泡实验其吸水率比不添加POE小10%。XRD分析及显微分析表明,除CaCO3自身结构影响外,添加不同增韧剂均未使PLA/稻壳复合材料形成新的晶型结构,加入POE和CaCO3的增韧效果不明显,是因为两种物质颗粒孤立存在于基体中,未形成相互搭连的网格结构。