Structure and properties of UHMWPE fiber/carbon fiber hybrid composites

Ultrahigh molecular weight polyethylene (UHMWPE) fiber/carbon fiber hybrid composites were prepared by inner‐laminar and interlaminar hybrid way. The mechanical properties, dynamic mechanical analysis (DMA), and morphologies of the composites were investigated and compared with each other. The results show that the hybrid way was the major factor to affect mechanical and thermal properties of hybrid composites. The resultant properties of inner‐laminar hybrid composite were better than that of interlaminar hybrid composite. The bending strength, compressive strength, and interlaminar shear strength of hybrid composites increased with an increase in carbon fiber content. The impact strength of inner‐laminar hybrid composite was the largest (423.3 kJ/m²) for the UHMWPE fiber content at 43 wt % to carbon fiber. The results show that the storage modulus (E′), dissipation factor (tan δ), and loss modulus (E″) of the inner‐laminar hybrid composite shift toward high temperature remarkably. The results also indicate that the high‐performance composite with high strength and heat resistance may be prepared by fibers' hybrid. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1880–1884, 2006     

Dielectric properties of cyanoethylated bagasse composites

Bagasse was converted into a thermo-moldable material by cyanoethylation. The effect of reaction conditions employed during the preparation of cyanoethylated bagasse (CE-B) fibers on dielectric properties of hot-pressed composites was studied. Increase in the nitrogen content of the cyanoethylated fiber, i.e., the nitrile groups resulted in an increase in the dielectric constant and a decrease in the dissipation factor (tan δ) peak of the composites. Increase in the reaction temperature and the alkali concentration resulted in a decrease in the dielectric constant and tan δof the composites. Thickness swelling (TS) and equilibrium moisture content of composites conditioned at different relative humidities (RHs) were studied and the extent of the effect of the absorbed moisture on the dielectric properties was also studied. Increase in the nitrogen content, the alkali concentration, and the reaction temperature during the preparation of cyanoethylated fibers resulted in a decrease in TS and moisture absorption of the composites formed. The dielectric properties of the composites conditioned at 60 or 90% RH deteriorated severely. The effect of temperature on the dielectric constant and tan δof a selected CE-B composite was studied. The dielectric constant and tan δincreased as the temperature increased.     

Interfacial adhesion study on UHMWPE fiber-reinforced composites

Ultrahigh molecular weight polyethylene (UHMWPE) fiber has many outstanding properties. However, poor interfacial adhesion of the UHMWPE fiber/polymer matrix interface limits its applications as reinforcement in high performance polymer matrix composites. Therefore, a new thermosetting resin system, named PCH, which is only composed of carbon and hydrogen elements, has been developed according to law of similar mutual solubility and the structural characteristics of UHMWPE fiber. The adhesion property was investigated by mechanical properties test, thermal performance test, and polymer solution properties test. Test results show that a strong interaction occurs between UHMWPE fiber and the PCH matrix due to the structural and polar similarity. In the case of slight difference between solubility parameters of UHMWPE fiber and cured PCH resin, it is found that the wettability of PCH resin on surface of the fiber can be improved and the difference between the coefficients of thermal expansion of the matrix and the fiber decreases with the increase of styrene added into the PCH. An optimal interfacial adhesion can be obtained as the ratio of PCH/styrene is approximately 55/45.     

PCH/UHMWPE复合材料的性能研究及应用

采用一种结构与超高分子量聚乙烯(UHMWPE)纤维相似、且对纤维表面具有良好浸润性的碳氢树脂(PCH)作基体,通过层压成型工艺制得PCH/UHMWPE复合材料,对复合材料的力学性能、介电性能及吸湿性能进行研究.结果表明,PCH/UHMWPE复合材料力学性能好、介电性能优异、吸湿率低,湿热前后材料性能变化甚小,性能保留率高,可用作高性能透微波复合材料.利用PCH/UHMWPE复合材料制得的覆铜板、压力容器等产品在实际应用中性能较为优异,可达到规定使用要求.     

Interfacial bond property of UHMWPE composite

The ultrahigh molecular weight polyethylene (UHMWPE)/hydrocarbon (PCH) composite was prepared by selecting a PCH resin as the matrix, which has the similar structure to UHMWPE fiber. The interfacial bond property between the PCH resin and UHMWPE fiber was investigated by macromechanics, micromechanics, and contact angle. The results show that the PCH resin has good wettability with the UHMWPE fiber surface. The UHMWPE/PCH composite has excellent transverse tensile strength, interlaminar shear strength, and the pull-out strength together with the outstanding interfacial bond property.     

Mechanical and thermal properties of epoxy-POSS reinforced-(biphenyl diol formaldehyde/epoxy hybrid resin) composites

To enhance the properties of epoxy composites, the biphenyl diol formaldehyde resin (BPFR) and glycidyloxypropyl polyhedral oligomeric silsesquioxane (G-POSS) were synthesized and used for modification of fiber-glass reinforced composites of epoxy resin (ER). The BPFR was employed to cure epoxy resin with different G-POSS contents and the laminates of fiber-glass reinforced hybrid composites prepared from BPFR, ER and G-POSS. The dynamic mechanical properties, thermal properties, mechanical and electrical properties of the hybrid composites were characterized by dynamic mechanical analyzer, thermogravimetric analyzer and electroproperty detector. The results showed that the T _g of the composites is increased with the addition of G-POSS. When the content of G-POSS is 5 wt%, the tensile and impact strength of the hybrid composites are 249.87 MPa and 63.83 kJ/m², respectively, which are all 30 % higher than those of non-added composites. At G-POSS content of 7 wt%, T _g of the material is 9.6 °C higher than pure BPFR/ER composite, and the initial decomposition temperature, T _id, is enhanced by about 29 °C. Dielectric constant, ε, and dielectric loss, tanδ, of the hybrid composites are between 0.53–0.7 and between 0.004–0.012, respectively.     

Physical and mechanical properties of kenaf/flax hybrid composites

This research investigates the physical and mechanical properties of hybrid composites made of epoxy reinforced by kenaf and flax natural fibers to investigate the hybridization influences of the composites. Pure and hybrid composites were fabricated using bi-directional kenaf and flax fabrics at different stacking sequences utilizing the vacuum-assisted resin infusion method. The pure and hybrid composites' physical properties, such as density, fiber volume fraction (FVF), water absorption capacity, and dimensional stability, were measured. The tests of tensile, flexural, interlaminar shear and fracture toughness (Mode II) were examined to determine the mechanical properties. The results revealed that density remained unchanged for the hybrid compared to pure kenaf/epoxy composites. The tensile, flexural, and interlaminar shear performance of flax/epoxy composite is improved by an increment of kenaf FVF in hybrid composites. The stacking sequence significantly affected the mechanical properties of hybrid composites. The highest tensile strength (59.8 MPa) was obtained for FK2 (alternative sequence of flax and kenaf fibers). However, FK3 (flax fiber located on the outer surfaces) had the highest interlaminar shear strength (12.5 MPa) and fracture toughness (3302.3 J/m²) among all tested hybrid composites. The highest water resistance was achieved for FK5 with the lowest thickness swelling.     

Experimental and simulated investigation of temperature distribution of UHMWPE laminated composites during hot pressing process

In this article, the influence of molding temperature on the mechanical properties and ballistic impact behavior of the ultrahigh molecular weight polyethylene (UHMWPE) laminated composites has been investigated. The results demonstrate that with the temperature increasing from 80 to 120 °C, the tensile strength decreases while the interlaminar bonding strength increases. The UHMWPE laminated composites manufactured by hot pressing of 75 layers UHMWPE fabrics show excellent ballistic performance when the molding temperature reaches 120 °C, indicating that dominant failure mechanism of the UHMWPE laminated composites are delamination, the fiber tension as well as bulging. Furthermore, a numerical model has been proposed to predict the temperature distribution of the UHMWPE laminated composites for a better understanding of the effect of molding temperature on the ballistic performance. The results show that the simulated results and experimental data are in good agreement. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45874.     

Carbon fiber cardanol-epoxy composites

Carbon fiber composites based on tetrafunctional epoxy resin N,N,N′,N′-tetraglycidyl-2,2-bis[4-(4-aminophenoxy)phenyl]propane modified with cardanol were investigated. The differential scanning calorimetric technique was used to study the curing reaction of the neat resins. The dielectric properties of the composites were compared. The use of cardanol in epoxy resins at cardanol/epoxy molar ratios less than 0.3/1 improved the chemical resistance as well as the mechanical properties of the composites, such as the flexural strength and modulus, tensile strength and modulus, and interlaminar shear strength. Higher cardanol contents decreased such properties. The highest properties of the composites were observed with the epoxy-cardanol resin having a cardanol/epoxy molar ratio of 0.3/1. © 1996 John Wiley & Sons, Inc.     

The effect of epoxidized natural rubber on mechanical properties of siliceous earth/natural rubber composites

Siliceous earth (SE) is a kind of mineral consisting of lamellar kaolinite, muscovite (aluminum silicate) and corpuscular silica. Natural rubber (NR) composites containing NR as matrix, epoxidized natural rubber (ENR) as compatibilizer and SE as filler were produced by latex coagulating process and cured using a conventional sulfuric system. Monsanto measurements have shown that the ENR accelerates the vulcanization reaction and gives rise to a marked increase of the torque. The results of physico-mechanical properties of NR vulcanizates show that, when SE modified by silane coupling agent and in the meanwhile adding 4 phr of ENR as compatibilizer, maximum tensile strength, elongation at break, reinforcing index (M300/100) of NR/SE vulcanizates were obtained. The dynamic-mechanical properties exhibit the addition of ENR can enhance wet grip characteristics and reduce rolling resistance by lowering tan δ values at 60 °C and increasing tan δ values at 0 °C of NR compounds. The overall results show that properties of SE-reinforced NR substantially improved by adding ENR as compatibilizer. The addition of silane coupling agent and combining an appropriate amount of ENR would be better choice to improve the properties of NR/SE compounds.     

Study on Mechanical and Dielectric Properties of Jute Fiber Reinforced Low-Density Polyethylene (LDPE) Composites

Abstract

Jute fiber (Hessian cloth) reinforced low-density polyethylene (LDPE) composites were prepared by heat press molding techniques. The mechanical properties such as tensile strength (TS), bending strength (BS), and elongation at break of the composites were studied. The enhancement of TS (33%) and BS (50%) were obtained as a result of reinforcment jute fabrics in LDPE. In order to improve the mechanical properties and adhesion between jute and LDPE, hessian cloth were each treated with 2-hydroxyl ethyl methacrylate (HEMA). The HEMA-treated jute composite showed higher tensile and bending strength compared to untreated jute composite and LDPE. Dielectric properties like dielectric constant and loss tangent (tan δ) of jute, LDPE and composites were studied. Ferro to paraelectric phase transition occurred in both treated and untreated jute composites containing more than 20% jute. Water uptake behaviors of the composite were monitored and HEMA-treated composite showed lower water absorption behavior. The adhesion nature of jute and LDPE also characterized by scanning electronic microscopy (SEM), better adhesion was observed between HEMA-treated jute and LDPE over untreated ones.     

Synthesis and characterization of fluorinated poly(etherimide)s toughening for carbon fiber‐reinforced epoxy composites

Novel‐fluorinated poly(etherimide)s (FPEIs) with controlled molecular weights were synthesized and characterized, which were used to toughen epoxy resins (EP/FPEI) and carbon fiber‐reinforced epoxy composites (CF/EP/FPEI). Experimental results indicated that the FPEIs possessed outstanding solubility, thermal, and mechanical properties. The thermally cured EP/FPEI resin showed obviously improved toughness with impact strength of 21.1 kJ/m² and elongation at break of 4.6%, respectively. The EP/FPEI resin also showed outstanding mechanical strength with tensile strength of 91.5 MPa and flexural strength of 141.5 MPa, respectively. The mechanical moduli and thermal property of epoxy resins were not affected by blending with FPEIs. Furthermore, CF/EP/FPEI composite exhibited significantly improved toughness with Mode I interlaminar fracture toughness (G_IC) of 899.4 J/m² and Mode II interlaminar fracture toughness (G_IIC) of 1017.8 J/m², respectively. Flexural properties and interlaminar shear strength of the composite were slightly increased after toughening. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers     

Hybrid effect on mechanical properties of M40‐T300 carbon fiber reinforced Bisphenol A Dicyanate ester composites

Interply and intraply hybrid composites based on Bisphenol A Dicyanate ester (BADCy), high strength carbon fibers T300, and high modulus carbon fibers M40 were prepared by monofilament dip‐winding and press molding technique. The tensile, flexural, interlaminar shear properties and SEM analysis of the hybrid composites with different fiber content and fiber arrangement were investigated. The results indicated that the mechanical properties of intraply hybrid composites were mainly determined by fiber volume contents. When the ratio of fiber volume content was close to 1:1, the intraply hybrid composites possessed lowest tensile and flexural strength. The mechanical properties of interply hybrid composite mainly depended on the fiber arrangement, instead of the fiber volume contents. The hybrid composites using T300 fiber layout as outside layer possessed high flexural strength and low flexural modulus, which was close to that of T300/BADCy composites. The hybrid composites ([(M40)_x/(T300)_y]_S) using M40 fiber layout as outside layer and T300 fibers in the mid‐plane had high flexural modulus and interlaminar shear strength. POLYM. COMPOS., 2010. © 2010 Society of Plastics Engineers     

Synthesis and Characterization of Lead-Free Ferroelectric 0.5[Ba(Zr0.2Ti0.8)O3]–0.5[(Ba0.7Ca0.3)TiO3]—Polyvinylidene Difluoride 0–3 Composites

0.5[Ba(Zr_0.2Ti_0.8)O₃]–0.5[(Ba_0.7Ca_0.3)TiO₃]/[BZT–BCT]–polyvinylidene difluoride/[PVDF] 0–3 composites were prepared by uniaxial hot-press method for different volume fractions of BZT–BCT ceramic powder in a PVDF polymer matrix. The structural, microstructural and dielectric properties were investigated and discussed. There was an increase in relative permittivity (ε_r) and dielectric loss (tan δ) of the composites with increase in the volume fraction of the ceramics. At room temperature and at 1 kHz frequency, 0.25[BZT–BCT]–0.75[PVDF] composite showed a highest relative permittivity (ε_r) ~41.     

Tuning the interlaminar shear strength and thermo-mechanical properties of glass fiber composites by incorporation of (3-mercaptopropyl) trimethoxysilane-functionalized carbon black

The incorporation of functionalized nanoscale fillers into traditional glass fiber/unsaturated polyester (GF/UPE) composites provides a more robust mechanical attributes. The current study demonstrates the potential of 3-mercaptopropyl trimethoxysilane (MPTS)-functionalized carbon black (f-CB) for enhancing the thermo-mechanical properties of GF composites. The composites infused with 1, 3 and 5 wt% of pristine and MPTS-functionalized CB were fabricated by hand lay-up and hot press processing. Tensile testing, interlaminar shear strength (ILSS) testing and dynamic mechanical analysis were used to evaluate the performance of nanocomposites. Fourier transform infrared spectroscopy validated the MPTS functionalization of CB. Pristine CB-loaded nanocomposites exhibited marginal improvement in ultimate tensile strength (UTS), ILSS and thermo-mechanical properties. However, with the addition of f-CB, the improvement in all the studied properties was more substantial. The inclusion of 5 wt% f-CB increased the elastic modulus and UTS by 16 and 22%, respectively, whereas the ILSS was enhanced by 36%, in comparison to the neat GF composite. The scanning electron microscope analysis of fractured ILSS samples revealed better fiber-matrix adhesion and compatibility in f-CB-loaded nanocomposites. At the same filler weight percentage, the storage modulus at 25 °C was ~ 19% higher than that of neat composite. The f-CB inclusion resulted in increment of T _g by ~ 13 °C over the T _g of neat GF/UPE composite (~ 109 °C). These improvements were due to the chemical connection of f-CB to the UPE matrix and GF surface. With such improvements in thermal and mechanical properties, these nanocomposites can replace the conventional GF composites with prominent improvements in performance.     

PP／UHMWPE原位成纤复合材料的混炼及成型工艺研究

采用超高分子量聚乙烯（ＵＨＭＷＰＥ）原位成纤增强、增韧聚丙烯（ＰＰ）。讨论了混炼剪切力、成型冷却方式和ＵＨＭＷＰＥ熔体熔点粘度对材料力学性能的影响。发现提高剪切力,加快冷却速度均有利于力学性能的提高,配比为９０／１０的ＰＰ／ＵＨＭＷＰＥ的缺口冲击强度、拉伸强度和断裂伸长率可达８８．６ｋＪ／ｍ＾２、４５．１ＭＰａ和５７０％,分别是ＰＰ－１３３０的３．５倍、１．５倍和２．５倍;而ＵＨＭＷＰＥ相对分子擀     

Preparation of POSS/Quartz fibers/cyanate ester resins laminated composites

Quartz fibers (QFs) and two polyhedral oligomeric silsesquioxane (POSS) (epoxy‐POSS and hydroxy‐POSS) are performed to regulate the dielectric properties, heat resistance, and mechanical properties of cyanate ester (CE) resins. With the introduction of POSS, the dielectric constant and dielectric loss tangent values of the POSS/QFs/CE laminated composites are decreased obviously. The heat resistance properties and flexural strength values of the laminated composites are increased, but the interlaminar shear strength values of the laminated composites are decreased slightly. The EP‐POSS/QFs/CE laminated composites have relatively better dielectric, heat resistance, and mechanical properties than those of HO‐POSS/QFs/CE laminated composites. POLYM. COMPOS., 36:2017–2021, 2015. © 2014 Society of Plastics Engineer     

脱蜡处理对石英布/氰酸酯复合材料的性能影响

对石英纤维布进行了高温脱蜡处理,并制成了石英布增强氰酸酯树脂基预浸料及其复合材料,对比了脱蜡处理前后预浸料的理化性能和工艺性的变化,以及复合材料介电性能和力学性能的变化。结果表明,脱蜡处理后的石英布/氰酸酯预浸料的工艺性能更好,复合材料的介电性能保持不变,力学性能显著提高,其中弯曲强度提高31%,层间剪切强度提高16%,脱蜡后界面结合更好。     

Obtaining complex-shaped oxide ceramic composites via ionotropic gelation

In this communication, we present a new processing method for obtaining oxide ceramic composites based on the ionotropic gelation technique. Nextel 610 fiber fabrics were infiltrated by an alumina-zirconia suspension with a total solid content of 50 vol% and alginate as the binder. Subsequently, the suspension was slowly cross-linked by adding Al³⁺ cations and transferred to a gel state. The gelled fabric layers could be easily cut, stacked and shaped, as well as joined to other ceramic materials and composites. Furthermore, the fiber content could be adjusted by pressing the layers together. In summary, the composites produced with this technique presented a very good fiber bundle infiltration, matrix with fine porosity and excellent mechanical properties. Nextel 610/alumina-zirconia composites sintered at 1200°C for 1 hour showed bending strength of 306 MPa, interlaminar shear strength of 9.8 MPa and nominal fracture toughness of 13.6 MPa m^0.5.     

Dynamic mechanical properties of the chemical oxidation on UHMWPE fibers for improved adhesion to epoxy resin matrix

The improved adhesion of an ultrahigh molecular weight polyethylene (UHMWPE) fiber to an epoxy from applying polypyrrole (PPy) was investigated using chemical oxidation polymerization. The interfacial shear strength of the PPy-treated fiber/epoxy was enhanced by 280%. Such an improvement was verified in the previous research using a pull-out test. Dynamic mechanical analysis (DMA) and a morphological examination were performed to evaluate the characteristics of the molecular motions of the UHMWPE fiber/PPy/epoxy composites. Two composite materials, a UHMWPE fiber/PPy and a UHMWPE fiber/PPy/epoxy, were tested by DMA. The results show that both the α_c transitions of the PPy-treated fibers and its composites shift toward higher temperature. In the SEM photos of the UHMWPE fiber/PPy, a very clear roughening effect on the surface of PPy-treated UHMWPE fiber was also observed, which contributes much to the modification of the interface to the epoxy. The results show that an adhesion improvement mechanism for the PPy-treaded UHMWPE fiber is due to the surface roughening effect and the intermolecular interaction. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1387–1395, 1998