The Mechanical and Physical Properties of Thermoplastic Natural Rubber Hybrid Composites Reinforced with Hibiscus cannabinus,L and Short Glass Fiber

Thermoplastic natural rubber hybrid composites reinforced with kenaf and short glass fibers were compounded by melt blending method using an internal mixer, Thermo Haake 600P. Thermoplastic natural rubbers (TPNR) were prepared from polypropylene (PP), natural rubber (NR) and liquid natural rubber (TPNR) with ratio 70:20:10, which were blended using internal mixer for 12 minutes at 180°C and rotor speed 40 r.p.m. Glass fiber was treated with silane coupling agent while TPNR reinforced kenaf fiber composite is using MAPP as a compatibilizer. TPNR hybrid composite with kenaf/glass fibers was prepared with fiber content (5, 10, 15, 20 volume % of fiber). Mechanical properties of the composites were investigated using tensile test^{[ 1} Anuar , H. ; Ahmad , S.H. ; Rasid , R. ; Wan Busu , W.N. Reinforced thermoplastic natural rubber hybrid composites with Hibiscus cannabinus, L and short glass fiber – Part I: Processing parameters and tensile properties . J. Compos. Mater. 2008 , 42 , 1075 – 1087 . [Google Scholar] ^], flexural, impact, and hardness test and scanning electron microscope (SEM)^{[ 1} Anuar , H. ; Ahmad , S.H. ; Rasid , R. ; Wan Busu , W.N. Reinforced thermoplastic natural rubber hybrid composites with Hibiscus cannabinus, L and short glass fiber – Part I: Processing parameters and tensile properties . J. Compos. Mater. 2008 , 42 , 1075 – 1087 . [Google Scholar] ^]. The incorporation of the treated or untreated fiber into TPNR has result in an increment of almost 100% of flexural modulus and impact strength as compared to TPNR matrix. However, the maximum strain decreased with increasing fiber content. The optimum composition for hybrid composite is at the fiber ratio of 30% kenaf fiber and 70% glass fiber. The SEM micrograph had shown, that the composite with coupling agent or compatibilizer promote better fiber-matrix interaction.     

聚丙烯/马来酸酐接枝聚丙烯/环氧树脂/玻璃纤维复合材料的制备及其性能研究

通过双螺杆挤出机制备了聚丙烯/马来酸酐接枝聚丙烯/环氧树脂/玻璃纤维（PP/PP-g-MAH/EP/GF）复合材料,并研究了PP-g-MAH含量、EP含量及固化剂对复合材料力学性能的影响。结果表明,PP-g-MAH含量为10份,含有固化剂EP的含量为3份时,复合材料的综合力学性能最佳;与不加EP的复合材料相比,其拉伸强度、弯曲强度、冲击强度分别提高了41 %、47 %、86 %。扫描电子显微镜分析表明,EP的加入明显改善了GF和PP基体的黏结强度。     

聚丙烯／玻璃纤维的界面改性研究（Ⅰ）：不同界面改性方法的比较

玻璃纤维增强聚丙烯复合材料的关键是提高非极性的聚丙烯和极性的玻璃纤维的界面粘结强度,本文比较了以双马来酰亚胺,聚丙烯－马来酸酐接枝共聚物,硅烷偶联剂作为界面剂的几种最为常见的界面改性方法对聚丙烯／玻璃纤维的界面改性效果,指出以聚丙烯－马来酸酐接枝共聚物作用面剂是最经济,最有效的聚丙烯／玻璃纤维的界面改性方法。     

玻纤增强PPESK复合材料及其性能研究

以溶液共混-共沉淀的方式制备了玻纤增强含二氮杂萘联苯结构的聚醚砜酮(PPESK)复合材料；考察了两种长度的玻纤对GF／PPESK复合材料力学性能的影响，并以较长的玻纤为例，通过SEM对复合材料的形态进行观察，用DSC和TGA对其热性能进行分析，同时分析偶联剂在复合材料中的作用。结果表明：较长的玻纤更有利于提高复合材料的力学性能；当GF含量为20％时，两种GF／PPESK复合材料的力学性能都达到最大。偶联剂的加入对于改善玻纤与PPESK的界面粘结、提高玻纤对PPESK的增强效果具有重要作用。随着玻纤含量的增加，复合材料的玻璃化转变温度和热降解温度都不同程度地提高。     

Enhanced Tensile and Dynamic Mechanical Properties of Thermoplastic Natural Rubber Nanocomposites

The melt compounding technique was employed to prepare thermoplastic natural rubber (TPNR) nanocomposites. The maleic anhydride grafted polyethylene (MA-PE) as a coupling agent was used to improve the filler-matrix interfacial adhesion. TPNR were prepared in the ratio of (70:20:10) from linear low-density polyethylene (LLDPE), natural rubber (NR) and liquid natural rubber (LNR) as a compatibilizer between the matrix. The composites were prepared using the in-situ method at the optimum processing parameter at 140°C with 100 rpm mixing speed and 12 minutes processing time. The results of the tensile test showed that the optimum of clay loading was obtained at 4 wt%. Dynamic mechanical analysis (DMA) was performed to investigate the thermomechanical properties of the composites. The results show that the addition of organoclay has improved the storage modulus (E′) and loss modulus (E′′) of TPNR nanocomposites. The α transition peaks was also shifted to the higher temperature. However, nanocomposites with MA-PE demonstrated higher, E′ and E′′ compared to TPNR nanocomposites without MA-PE. The TEM results show good clay dispersion with a combination of intercalated-exfoliated structure in the TPNR matrix.     

Effects of rice husk (RH) particle size,glass fiber (GF) length,RH/GF ratio,and addition of coupling agent on the mechanical and physical properties of polypropylene‐RH‐GF hybrid composites

Polypropylene (PP) hybrid composites based on rice husk (RH) with different particle size and glass fiber (GF) with different length were prepared. The composites were subjected to mechanical and water immersion tests. From the results obtained, it was found that the mechanical properties of the hybrid composites were strongly dependent on the size of RH particle and length of GF. It could be further enhanced with the presence of coupling agent. In this study, two types of coupling agents, i.e., Epolene E‐43 (E‐43) and 3‐(trimethoxysilyl)‐propylmethacrylate (TPM), were employed. In general, E‐43 imparted significant improvement in the mechanical properties. From the water immersion results, it was found that the hydrophobicity of the composites was increased with the presence of coupling agent. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

高强高韧GF／PP复合材料的研究

通过在短玻(GF)增强聚丙烯(PP)中添加聚烯烃弹性体(POE),并用马来酸酐对PP进行接枝交联的方法, 制备了高冲击韧性GF／PP复合材料。在该材料中,短切玻璃纤维的加入大幅度提高了材料的拉伸、弯曲强度,而POE 则通过产生形变等方式,提高了材料的冲击韧性;在其中加入马来酸酐接枝聚丙烯增加界面结合力,可使GF／PP／POE 复合体系表现出良好的综合力学性能,其拉伸强度为51．9 MPa,弯曲强度为68．1MPa,冲击韧性为44．2 kJ／m2。     

相容剂对玻纤增强尼龙6流变行为的影响

通过熔融挤出制备了含有不同用量相容剂马来酸酐接枝线性低密度聚乙烯（LLDPE-g-MAH）和硅烷偶联剂的玻璃纤维（GF）增强尼龙6（PA6）复合材料，并用毛细管流变仪研究了复合材料的流变行为，得到了熔体流变性能关系曲线。结果表明，不管是否存在硅烷偶联剂，PA6／GF／相容剂复合材料的流变行为符合假塑性流体的流动规律，非牛顿性比PA6／GF强，表观粘度随温度升高和剪切速率的增加而降低。随着相容剂用量的增加，复合材料的表观粘度不断增大，而非牛顿指数变小，而且流动活化能变小。     

硅烷偶联剂对玻纤/聚丙烯复合材料的影响

分别选用KH550、KH570两种硅烷偶联剂处理无碱无捻粗纱,采用挤出、注塑成型技术制备玻纤增强聚丙烯复合材料,对复合材料进行了分析和研究。结果表明：硅烷偶联剂具有提高GF/PP复合材料性能的作用。SEM显示KH570处理GF与PP基体之间形成了良好的界面,界面层起到很好的应力传递作用,达到良好的增强效果。     

Effects of fiber‐surface treatment on the properties of hybrid composites prepared from oil palm empty fruit bunch fibers,glass fibers,and recycled polypropylene

In this article, we report the effects of hybridization and fiber‐surface modification on the properties of hybrid composites prepared from recycled polypropylene (RPP), coupling agents, oil palm empty fruit bunch (EFB), and glass fibers through a twin‐screw extruder and an injection‐molding machine. The surface of the EFB fibers was modified with different concentrations (10–15 wt %) and temperatures (60–90°C) of alkali solutions. The structure and morphology of the fibers were observed with the help of Fourier transform infrared spectroscopy and scanning electron microscopy. Different types of composites were fabricated with untreated, alkali‐treated, and heat‐alkali‐treated fibers. Comparative analysis of the mechanical, structural, morphological, and thermal properties of the composites was carried out to reveal the effects of treatment and hybridization. The analysis results reveal that composites prepared from the alkali‐treated (in the presence of heat) fibers show improved mechanical, thermal, and morphological properties with a remarkably reduced water absorption. Additionally, the crystallinity of RPP also increased with the development of biaxial crystals. The improvement of various properties in relation to the structures and morphologies of the composites is discussed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43049.     

Injection‐molded short hemp fiber/glass fiber‐reinforced polypropylene hybrid composites—Mechanical,water absorption and thermal properties

Natural fiber‐based thermoplastic composites are generally lower in strength performance compared to thermoset composites. However, they have the advantage of design flexibility and recycling possibilities. Hybridization with small amounts of synthetic fibers makes these natural fiber composites more suitable for technical applications such as automotive interior parts. Hemp fiber is one of the important lignocellulosic bast fiber and has been used as reinforcement for industrial applications. This study focused on the performance of injection‐molded short hemp fiber and hemp/glass fiber hybrid polypropylene composites. Results showed that hybridization with glass fiber enhanced the performance properties. A value of 101 MPa for flexural strength and 5.5 GPa for the flexural modulus is achieved from a hybrid composite containing 25 wt % of hemp and 15 wt % of glass. Notched Izod impact strength of the hybrid composites exhibited great enhancement (34%). Analysis of fiber length distribution in the composite and fracture surface was performed to study the fiber breakage and fracture mechanism. Thermal properties and resistance to water absorption properties of the hemp fiber composites were improved by hybridization with glass fibers. Overall studies indicated that the short hemp/glass fiber hybrid polypropylene composites are promising candidates for structural applications where high stiffness and thermal resistance is required. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2432–2441, 2007     

Flame retardant synergy between interfacial and bulk carbonation in glass fiber reinforced polypropylene

Glass fiber reinforced polypropylene (GF-PP) composites have high flammability on account of wick effect which leads to accelerated flow of the polymer melt along the glass fibers (GF) surface to the flame zone. In this study, dipentaerythritol (DPER), a charring agent, was adsorbed on the GF surface through the hydrogen bond between silane coupling agent and DPER. DPER has a synergistic effect with the intumescent flame retardants (IFR) added in the composites, which can induce interfacial carbonization on the surface of GF, thus transforming the intrinsic smooth GF surface into roughness one. In this way, the negative effect of the wick effect in flame retardancy is weakened. Moreover, the char residues remained on the surface of GF can bring an improved adhesion between GF and char residues formed in the resin so that a more stable barrier char layer is formed. The PP composites with 20 wt% modified glass fiber (M-GF) and 30 wt% IFR can achieve the UL-94V-0, and its limiting oxygen index (LOI) value increased from 16.5% to 29.5%. Simultaneously, the heat release rate (HRR), total heat release (THR) and total smoke release (TSR) decreased significantly, and the peak of heat release rate (PHRR) reduced 60.6% compared with GF-PP.     

Thermo-mechanical and mechanical behavior of hybrid isotactic polypropylene glass fiber reinforced composites (GFRC) modified with calcium carbonate (CaCO3)

The study investigates the thermo-mechanical properties of isotactic polypropylene (iPP) hybrid composites in reference to various amounts of particle- and fiber-shaped inorganic fillers. Three grades of hybrid composites were prepared as a function of filler amount: 5, 10, and 20 wt% and different ratios of glass fiber (GF) and calcium carbonate (CaCO₃). The main objective is to describe the relationship between the hybridization efficiency and mechanical performance of polypropylene-based composites. The analysis of the thermo-mechanical properties of the composites shows that both the total amount of the filler and the ratio of GF and CaCO₃ clearly influence the properties of the composites. Hybrid composites with the highest amount of the GF display improved thermo-mechanical stability. The presence of well-dispersed CaCO₃ in the composites was found to improve elongation at break and Vicat softening temperature values. Even though it is glass fiber, which shows higher filler effectiveness and visibly reinforces the composite samples, causing an increase in tensile strength or reinforcing efficiency, replacing up to 50% of this filler with calcium carbonate does not result in a considerable deterioration of the properties of the material.     

废弃木粉与短切玻璃纤维组合增强聚丙烯的力学性能

用废弃木粉与短切玻璃纤维作为增强材料，制得了组合增强的聚丙烯复合材料，研究了制备工艺及设备、材料配方及界面改性方法等对材料力学性能的影响。结果表明，用单螺杆挤出机制备组合增强材料，可减少对玻璃纤维的损伤，保持较长的玻璃纤维，有利于其增强作用的发挥；随着玻璃纤维含量的增加，体系的力学性能提高，而木粉含量对材料力学性能的影响与玻璃纤维的含量相关；采用硅烷偶联剂对木粉进行表面处理，在基体中添加接枝极性基团的改性聚丙烯，可改善体系的界面结合，提高力学性能。     

注塑工艺制备玻璃纤维增强聚合物研究

采用碱性短玻璃纤维增强PP,通过混合-注塑工艺制备玻璃纤维/PP复合材料,并较全面的研究了玻纤含量、长度、偶联剂类型与加入量对复合材料力学性能的影响。结果表明:随着玻纤含量的增加,复合材料的力学性能有明显的提高,增加到35%时性能最佳;并且发现纤维长度越长,增强的幅度越大;随着注塑次数的增多,聚合物的拉伸强度先大后小,证实3次较好;说明用注塑法来制备短纤维增强PP复合材料是完全可行的。     

Mechanical properties and dynamic mechanical analysis of thermoplastic‐natural‐rubber‐reinforced short carbon fiber and kenaf fiber hybrid composites

The hybridization of thermoplastic natural rubber based on carbon fiber (CF) and kenaf fiber (KF) was investigated for its mechanical and thermal properties. Hybrid composites were fabricated with a melt‐blending method in an internal mixer. Samples with overall fiber contents of 5, 10, 15, and 20 vol % were subjected to flexural testing, and samples with up to 30% fiber content were subjected to impact testing. For flexural testing, generally, the strength and modulus increased up to 15 vol % and then declined. However, for impact testing, higher fiber contents resulted in an increment in strength in both treated and untreated composites. Thermal analysis was carried out by means of dynamic mechanical analysis on composites with 15 vol % fiber content with fractions of CF to KF of 100/0, 70/30, 50/50, 30/70, and 0/100. Generally, the storage modulus, loss modulus, and tan δ for the untreated hybrid composite were more consistent and better than those of the treated hybrid composites. The glass‐transition temperature of the treated hybrid composite was slightly lower than that of the untreated composite, which indicated poor damping properties. A scanning electron micrograph of the fracture surface of the treated hybrid composite gave insight into the damping characteristics. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Banana/Glass Fiber-Reinforced Polypropylene Hybrid Composites: Fabrication and Performance Evaluation

Hybrid composites of Polypropylene (PP) reinforced with intimately mixed short banana and glass fibers were fabricated using Haake twin screw extruder followed by compression molding with and without the presence maleic anhydride grafted polypropylene (MAPP) as a coupling agent. Incorporation of both the fibers into PP matrix resulted in an increase in tensile, flexural and impact strength with an increasing level of fiber content upto 30 wt% at banana: glass fiber ratio of 15:15 wt% and 2 wt% of MAPP. The rate of water absorption for the hybrid composites decreased due to the presence of glass fiber and coupling agent. The effect of fiber loading in presence of coupling agent on the dynamic mechanical properties has also been analyzed to investigate the interfacial properties. An increase in the storage modulus (E′) of the treated composite indicates higher stiffness. The tan δ spectra confirms a strong influence of fiber contents and coupling agent on the α and β relaxation processes of PP. The nature of fiber matrix adhesion was examined through scanning electron microscopy (SEM) of the tensile fractured specimen. Thermal measurements were carried out employing differential scanning calorimetry (DSC) and the thermogravimetric analysis (TGA) which indicated a decrease in the crystallization temperature and thermal stability of PP with the incorporation of MAPP treated banana and Glass fiber.     

偶联剂对玻璃纤维增强POM性能的影响

研究了玻璃纤维(GF)含量、偶联剂的种类与添加量对复合材料力学性能的影响。结果表明:偶联剂的加入,不仅使GF均匀分布在聚甲醛(POM)基体中,而且使复合材料的结构及性能有较大的改善。随着偶联剂和玻璃纤维含量的增加,复合材料的力学性能明显提高。     

Influences of liquid elastomer additive on the behavior of short glass fiber reinforced epoxy

In this study, improvements in mechanical and thermal behavior of short glass fiber (GF) reinforced diglycidyl ether of bisphenol-A (DGEBA) based epoxy with hydroxyl terminated polybutadiene (HTPB) modification have been studied. A silane coupling agent (SCA) with a rubber reactive group was also used to improve the interfacial adhesion between glass fibers and an epoxy matrix. 10, 20, and 30 wt% GF reinforced composite specimens were prepared with and without silane coupling agent treatment of fibers and also HTPB modification of epoxy mixture. In the ruber modified specimens, hardener and HTPB were premixed and left at room temperature for 1 hr before epoxy addition. In order to observe the effects of short glass fiber reinforcement of epoxy matrix, silane treatment of fiber surfaces, and also rubber modification of epoxy on the mechanical behavior of specimens, tension and impact tests were performed. The fracture surfaces and thermal behavior of all specimens were examined by scanning electron microscope (SEM), and dynamic mechanical analysis (DMA), respectively. It can be concluded that increasing the short GF content increased the tensile and impact strengths of the specimens. Moreover, the surface treatment of GFs with SCA and HTPB modification of epoxy improved the mechanical properties because of the strong interaction between fibers, epoxy, and rubber. SEM studies showed that use of SCA improved interfacial bonding between the glass fibers and the epoxy matrix. Moreover, it was found that HTPB domains having relatively round shapes formed in the matrix. These rubber domains led to improved strength and toughness, due mainly to the “rubber toughening” effect in the brittle epoxy matrix.     

Effect of rare earth elements' surface treatment on tensile properties and microstructure of glass fiber–reinforced polytetrafluoroethylene composites

Three types of surface modifiers, N‐β‐aminoethyl‐γ‐aminopropyltrimethoxysilane coupling agent (SGS), a mixture of silane and rare earth elements (SGS/RES), and rare earth elements surface modifier (RES), were used to treat the glass fiber surface. Tensile tests of glass fiber–reinforced polytetrafluoroethylene (GF/PTFE) composites with different surface treatment conditions, surface modifiers, and glass fiber content were carried out. Finally, the fracture surface morphologies of GF/PTFE composites were investigated using scanning electron microscopy. Experimental results show that the tensile properties of the treated GF/PTFE composite increased compared with those of the untreated one. RES is superior to SGS/RES and SGS modifiers in promoting interfacial adhesion between the glass fiber and PTFE because of the effects of rare earth elements on the compatibility. Meanwhile, the optimum contents of rare earth elements for the improvement of the tensile properties of GF/PTFE composite were obtained for RES and SGS/RES modifiers. The interfacial adhesion of the GF/PTFE composites treated with RES or SGS/RES modifiers was mainly controlled by the contents of rare earth elements. The tensile properties of the GF/PTFE composites improved considerably when the content of rare earth elements in surface modifiers was 0.2–0.4 wt %, and the optimum tensile performance of GF/PTFE composites was obtained at 0.3 wt % RE content. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1667–1672, 2002