长玻璃纤维增强聚丙烯复合材料热模压成型工艺的研究

为了提高LGFRP模压制品的基本力学性能及其性能的稳定性,把热模压成型过程细分为预热工序、模压工序和成型操作三个部分,分别对应片材加热温度、保温时间、成型压力、模具温度、保压时间、坯料转移时间以及模压排气次数七个热模压成型工艺参数,运用正交试验和单因素试验方法,分析和讨论了各工艺参数对LGFRP复合材料热模压件力学性能的影响,并优化出了较佳的工艺参数组合。结果表明,工艺参数对力学性能的影响度大小受工艺条件的影响,并且细化成型工艺可提高LGFRP热模压制品的力学性能与热模压工艺的稳定性。     

基于极差分析的SMC复合材料模压工艺参数优化

为了探讨模压成型参数对于片状模塑料（SMC）材料模压制品综合力学性能的影响,将模压成型过程分为3个阶段,以3个阶段的压力与时间共6个参数作为影响因子,对制品的拉伸强度、弯曲强度与冲击强度进行测试,设计了正交试验,以制品的力学性能作为评价指标,采用极差分析法,分析讨论了各阶段工艺参数对SMC复合材料制品力学性能的影响,并结合成型过程中材料状态变化分析造成实验结果的原因,最终得到优化后的工艺参数。     

芳纶短纤维/聚氨酯树脂复合材料成型工艺研究

成型工艺直接影响复合材料的性能。本文考察了芳纶短纤维/聚氨酯树脂复合材料模压成型工艺的预成型时间、模压温度、模压压强、模压时间等因素对复合材料拉伸强度的影响。结果表明,预成型时间4h,模压温度170℃,模压压强为4MPa,模压时间为30m in的工艺条件下可制备拉伸强度为35 MPa的芳纶短纤维/聚氨酯树脂复合材料。     

健身器械用碳纤维复合材料成型与性能研究

研究了模压温度、模压压力和模压时间对健身器械用碳纤维/聚碳酸酯复合材料宏观形貌、0°和45°方向拉伸性能和冲击性能的影响。结果表明,随着模压温度的升高,碳纤维/聚碳酸酯复合材料的拉伸强度和冲击功呈现先增加而后减小的特征,在模压温度为240℃时取得最大值;随着模压压力的升高,碳纤维/聚碳酸酯复合材料在0°和45°方向的拉伸强度都呈现先增加而后减小的特征,当模压压力为6MPa,碳纤维/聚碳酸酯复合材料具有最佳拉伸强度和冲击韧性结合。随着模压时间的延长,碳纤维/聚碳酸酯复合材料在0°和45°方向的拉伸强度都呈现先增加而后减小的特征,在模压时间为10min时取得最大值。碳纤维/聚碳酸酯复合材料的适宜的模压成型工艺参数为:模压温度240℃、模压压力6MPa、模压时间10min。     

环氧树脂/碳纤维复合材料模压制品冲击强度影响因素分析

通过正交试验研究了模压温度、模压压力、保压时间、合模速度对环氧树脂/碳纤维片状模塑料模压成型制品冲击强度的影响,制品冲击强度表现出显著的各向异性。使用极差法证明各因素对冲击强度的影响大小为：保压时间t>合模速度v>模压温度T>模压压力P;得到最佳工艺参数组合为：模压温度T为130℃、模压压力P为500 kN、保压时间t为540 s、合模速度v为1 mm/s,使用该参数组进行验证实验,新制品冲击强度相较于正交试验中的最大值提高了9.75%。结合典型冲击断裂试样的微观形貌解释了影响因素作用于制品冲击强度的微观机制。     

酚醛树脂复合材料成型条件的正交实验优化

采用正交实验研究了模压时间、模压温度、模压压力和预热时间等4个因素对复合材料性能的影响。正交实验结果表明:模压时间是弯曲强度、缺口冲击强度和无缺口冲击强度的最主要影响因素,预热时间是拉伸强度、热变形温度和电气强度的最主要影响因素。通过正交实验获得的优选实验方案为:模压时间为4 min,模压温度为170℃,模压压力为15 MPa,预热时间为10 min。     

模压工艺对聚酰亚胺树脂力学性能的影响

以均苯四甲酸二酐、4,4'-双(氨基苯氧基)二苯砜为主要单体,制备了模压级聚酰亚胺(PI)树脂,并对该树脂的模压成型工艺进行了研究。考察了模压温度、模压压力和模压时间对PI制件拉伸强度、弯曲强度和压缩强度的影响。结果表明:该PI树脂的最佳模压工艺条件为模压温度350℃、模压压力18 MPa、模压时间120min。在该条件下,所制PI制件的拉伸强度、弯曲强度和压缩强度分别为108.6、145.8、139.8 MPa。     

SMC模压成型工艺参数对成型质量的影响

通过模压实验研究了不饱和聚酯树脂片状模塑料(SMC)模压成型工艺参数对制品成型质量的影响;以冲击强度为衡量制品性能的定量指标,通过正交实验得到了优化的SMC模压成型工艺参数,分析了各参数对冲击强度的影响,对实际生产具有一定的指导意义.     

铁路建设轨枕用高性能复合材料的制备与应用研究

采用薄膜层叠模压成型工艺制备铁路建设轨枕用高性能碳纤维织物/聚碳酸酯复合材料,研究模压温度、模压压力和模压时间对复合材料宏观形貌、拉伸性能和冲击性能的影响。结果表明,从碳纤维/聚碳酸脂复合材料的宏观形貌上看,模压温度、模压压力和模压时间分别应该控制在245℃及以下、6 MPa及以下和10 min及以下;从碳纤维/聚碳酸酯复合材料的力学性能上看,轨枕用高性能复合材料的最佳制备工艺：模压温度245℃、模压压力6 MPa、模压时间10 min,复合材料的0°、45°拉伸强度分别为377、99 MPa,冲击功为1.36 J。     

一种装饰用碳纤维复合材料锻造成型新工艺及拉伸性能研究

为了提升室内设计中碳纤维复合材料的拉伸性能,提出一种锻造成型的新工艺。研究了模压压力、加压温度、固化温度、保温时间等参数对碳纤维复合材料拉伸性能的影响。结果表明,随着模压压力、加压温度、固化温度、保温时间增加,碳纤维复合材料的拉伸强度和标准化拉伸强度先增大后减小;适宜的碳纤维复合材料的成型工艺参数为：模压压力为10 MPa、加压温度110℃、固化温度140℃、保温时间30 min;碳纤维复合材料拉伸过程中主要有3种破坏形式：纤维拔出、树脂断裂和内聚破坏,最佳工艺参数下碳纤维复合材料的断裂方式为内聚破坏。     

注射压缩成型聚碳酸酯制品的低温拉伸力学性能

以聚碳酸酯为材料,利用自行设计带有压缩功能的模具,采用常规注塑成型(IM)和注射压缩成型方法(ICM)对比研究制品在常温和低温环境下的拉伸力学性能;基于单因素实验方法,研究熔体温度、模具温度、模板压缩距离、延迟时间和压缩力对ICM制品残余应力和低温拉伸性能的影响规律。结果表明:在相同的环境温度下,ICM制品较IM制品有较大的屈服应力和弹性模量;低温环境下样品的拉伸性能有所提升,并在-40℃附近出现了聚碳酸酯分子的次级玻璃化转变;残余应力是影响ICM制品低温拉伸性能的主要因素,较高的熔体温度、模具温度、模板压缩距离,以及较短的延迟时间,较小的压缩力会减小ICM制品的残余应力,提高制品的低温拉伸性能。     

微孔发泡聚碳酸酯片材的制备与性能研究

在聚碳酸酯(PC)的玻璃化温度(tg)和熔融温度(tm)之间，采用模压法制备出用挤出、注射和常规发泡难以加工成型的薄型微孔发泡PC片材。模压法有制备周期短、工艺简单、操作容易、价格低廉等优点。通过热性能及力学性能测试．表明用模压法制备的微孔发泡PC片材性能优异。     

塑化温度和成型温度对增塑PVC及PVC／PNBR弹性体力学性能的影响

当塑化温度分别为135℃和150℃时,通过测定不同成型温度下（145、150、155、160℃）压片制得的增塑PVC和PVC／PNBR共混物的断裂伸长率、拉伸强度、硬度和拉伸永久变形,研究了塑化温度和成型温度对试样力学性能的影响。结果表明：①150℃塑化温度下,物料塑化得更完全,PVC分子链间的作用力增强,试样的拉伸强度、拉伸永久变形、硬度增大;②在成型温度为145-155℃范围内,试样的断裂伸长率、拉伸强度随成型温度的提高都显著增大;③与塑化温度相比,成型温度对试样力学性能的影响更大。     

Optimization of thermopressing conditions for the production of binderless boards from a coriander twin‐screw extrusion cake

A deoiled press cake resulting from twin‐screw extrusion of coriander fruits was used as a raw material for the production of self‐bonded boards. The operating parameters for thermopressing were varied and include the applied pressure (19.6–39.2 MPa), molding time (60–300 s), and molding temperature (155–205 °C). The optimized process conditions (21.6 MPa, 300 s, 205 °C) resulted in a board with a density of 1323 kg/m³, a flexural strength of 23 MPa, a modulus of elasticity of 4.4 GPa, and a thickness swelling of 31%. The thickness swelling was effectively reduced to 20% through the application of a heat treatment at 200 °C after thermopressing. A variation of the moisture content of the press cake between 3 and 8% showed that increased moisture contents do not lead to improved mechanical properties of the resulting board and further induce internal fracturing of the board during thermopressing. The manufactured binderless boards may act as environmentally friendly alternatives to commercial wood‐based boards such as oriented strand board and particleboard. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44650.     

In situ composites from blends of polycarbonate and a thermotropic liquid‐crystalline polymer: The influence of the processing temperature on the rheology,morphology, and mechanical properties of injection‐molded microcomposites

This work was aimed at understanding how the injection‐molding temperature affected the final mechanical properties of in situ composite materials based on polycarbonate (PC) reinforced with a liquid‐crystalline polymer (LCP). To that end, the LCP was a copolyester, called Vectra A950 (VA), made of 73 mol % 4‐hydroxybenzoic acid and 27 mol % 6‐hydroxy‐2 naphthoic acid. The injection‐molded PC/VA composites were produced with loadings of 5, 10, and 20 wt % VA at three different processing barrel temperatures (280, 290, and 300°C). When the composite was processed at barrel temperatures of 280 and 290°C, VA provided reinforcement to PC. The resulting injection‐molded structure had a distinct skin–core morphology with unoriented VA in the core. At these barrel temperatures, the viscosity of VA was lower than that of PC. However, when they were processed at 300°C, the VA domains were dispersed mainly in spherical droplets in the PC/VA composites and thus were unable to reinforce the material. The rheological measurements showed that now the viscosity of VA was higher than that of PC at 300°C. This structure development during the injection molding of these composites was manifested in the mechanical properties. The tensile modulus and tensile strength of the PC/VA composites were dependent on the processing temperature and on the VA concentrations. The modulus was maximum in the PC/VA blend with 20 wt % VA processed at 290°C. The Izod impact strength of the composites tended to markedly decrease with increasing VA content. The magnitude of the loss modulus decreased with increasing VA content at a given processing temperature. This was attributed to the anisotropic reinforcement of VA. Similarly, as the VA content increased, the modulus and thus the reinforcing effect were improved comparatively with the processing temperature increasing from 280 to 290°C; this, however, dropped in the case of composites processed at 300°C, at which the modulus anisotropy was reduced. Dynamic oscillatory shear measurements revealed that the viscoelastic properties, that is, the shear storage modulus and shear loss modulus, improved with decreasing processing temperatures and increasing VA contents in the composites. Also, the viscoelastic melt behavior (shear storage modulus and shear loss modulus) indicated that the addition of VA changed the distribution of the longer relaxation times of PC in the PC/VA composites. Thus, the injection‐molding processing temperature played a vital role in optimizing the morphology‐dependent mechanical properties of the polymer/LCP composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

The effect of injection molding process parameters on mechanical and fracture behavior of polycarbonate polymer

In this work, the mechanical and failure behavior of injection molded aviation standard optical grade polycarbonate (PC) was investigated through uniaxial tensile testing. The effect of different injection molding process parameters including injection velocity, packing pressure, cooling time, mold temperature, and melt temperature were determined to observe their effect on yield and postyield behavior of PC. Out of these examined parameters, the mold and melt temperature show significant effect on mechanical behavior of studied polymer. The yield and flow stresses in polymer increase with the increase in mold and melt temperature during injection molding. However, other process parameters i.e., packing pressure, injection velocity, and cooling time showed little effect on mechanical performance of the polymer. The molded specimens were annealed at different temperatures and residence time to evaluate its effect on mechanical behavior and fracture morphology. The yield stress increases gradually with the increase in annealing temperature and time. The annealing treatment also changed the failure mode of PC specimens from ductile to brittle. In addition to process parameters, the effect of increased loading rate was also undertaken which shows substantial effect on mechanical and failure behavior of PC. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44474.     

双马来酰亚胺改性氰酸酯树脂及其复合材料

制备了一种新型的双马来酰亚胺改性氰酸酯树脂以提高这类树脂的耐热性,力学性能及成型工艺性。对合成的树脂作了流变分析,对其玻纤复合材料进行了力学性能测试和热失重分析,结果表明,当双马树脂达到改性氰酸酯树脂的质量分数的37.5%时,新型改性氰酸酯树脂的5%热失重温度为432℃。改性氰酸酯基复合材料在常温条件下的拉伸强度为492.4 MPa,弯曲强度为526.3 MPa。在200℃时改性氰酸酯基复合材料的拉伸强度为357.3 MPa,弯曲强度为292.7 MPa。该树脂具有良好的加工性,耐热性,力学性能及高温力学保持性。     

SEBS-g-MAH和EP复合增容PA610/PC合金的研究

选用SEBS-g-MAH和EP为复合增容剂,采用熔融挤出的方法制备了PA610/PC合金,研究了该合金的力学性能、熔融结晶及微观结构形态。结果表明,当PA610/SEBS-g-MAH(EP)/PC组分比为75/9(2)/25时,合金的冲击强度比不加增容剂时提高了281.4%,断裂伸长率提高了346.0%。而增容剂的加入使合金中PA610的结晶温度升高,结晶速率增大而结晶度降低,由于异相成核作用使结晶发生细化,使得韧性提高、熔点降低。微观结构形态研究表明,在只加入SEBS-g-MAH的PA610/PC合金中,合金断面有很多PC被拔出及余留空洞的现象;在加入EP协同增容后,PC被拔出的现象减少,与PA610基体的界面粘合增强,空洞消失。     

Modification of polycarbonate by adding poly(L‐lactide)

In this study, the blend of polycarbonate (PC)/poly(L‐lactide) (PLLA) (70/30) was prepared through the conventional extrusion‐injection‐molding process. The morphology of the blend was characterized using scanning electron microscope. Both differential scanning calorimetry and wide angle X‐ray diffraction were used to investigate the crystallization behavior of PLLA component in the blend. The mechanical and thermal properties of the blend were comparatively investigated, and the hydrolytic degradation ability of the material was also evaluated. The results show that the dispersed‐PLLA particles are in the amorphous state in the PC matrix. Although the blend is immiscible, the rigid PLLA particles exhibit the toughening and reinforcement effects on PC simultaneously. Specifically, the heat‐distortion temperature of the blend is comparable to that of pure PC. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

电磁动态注塑对等规聚丙烯增韧和增强研究

利用普通注射成型和电磁动态注塑机注射成型制备等规聚丙烯试样，并对其进行拉伸强度、冲击强度、差示扫描量热仪（DSC）和广角X射线衍射（WAXD）测试。对动态与稳态注射成型聚丙烯制品的力学性能进行了比较，并结合微观测试结果，深入探讨了制品微观结构与力学性能之间的关系。力学测试结果表明，动态成型制品的拉伸性能和冲击性能比稳态加工条件下都有所提高，尤其是制品冲击性能的提高幅度可以达到40％以上，实现了对制品的同时增强和增韧。DSC和WAXD测试表明，动态成型制品的结晶比稳态制品完善，并且晶粒尺寸也小于稳态制品。经过理论分析，认为结晶情况的改善是制品拉伸强度提高的原因，而晶粒细化则大幅度提高了制品的冲击强度。