热致液晶性纤维素芳族酯与聚碳酸酯挤出──拉伸原位复合的研究

将自制热致液晶性纤维素芳族酯（ＡＥＣ）与聚碳酸酯（ＰＣ）通过挤出——拉伸工艺制得了原位增强的ＰＣ／ＡＥＣ复合综丝。研究结果表明：复合综丝强度与ＡＥＣ取向微纤的尺寸和数量密切相关，５％用量的ＡＥＣ可使综丝强度提高３５％；综丝的双折射率△ｎ实质上反映了ＡＥＣ液晶微纤的数量和取向度，可以通过△ｎ将不同组成比和拉伸比的综丝与其强度关联起来。     

热致液晶聚合物与聚醚砜原位复合材料再加工性能的研究

本文研究了热致液晶聚合物ＴＬＣＰＫＵ９２３１和聚醚砜（ＰＥＳ）原位复合材料的再加工性能，在ＰＥＳ中加入２５ωｔ％的ＴＬＣＰＫＵ９２３１，拉伸强度大幅度提高，再次加工时拉伸强度虽略有下降，但仍远远高于ＰＥＳ的拉伸强度．随着循环加工次数增加，拉伸强度明显下降．     

填料改性UHMWPE基复合材料拉伸磨损性能的研究

研究了填料颗粒改性的超高分子量聚乙烯（ＵＨＭＷＰＥ）体系的拉伸与磨损性能。加入少量的粉煤灰（＜１０％）和ＳｉＣ（３０％）可提高体系的拉伸强度，并且颗粒越细小，越有利于拉伸强度的提高。ＳｉＣ，Ａｌ２Ｏ３，特别是４０目石英砂可大幅度提高（约４～６倍）体系的耐磨料磨损能力。试验结果表明，载荷Ｐ是影响ＵＨＭＷＰＥ体系磨损率的重要因素。载荷越大，磨损率越高，而与相对摩擦速度ｖ关系不大。所得结果为减粘耐磨复合材料的仿生设计提供了可靠的依据     

PVAC／PP复合纤维的结构与性能研究

热重（ＴＧ）的结果表明，聚醋酸乙烯酯（ＰＶＡＣ）与聚丙烯（ＰＰ）共混后，其热稳定性增加。同时用Ｘ射线衍射及双折射等方法研究了ＰＶＡＣ／ＰＰ复合纤维的结构与力学性能的关系．发现拉伸倍数提高，纤维力学性能及ＰＰ结晶度增大，在体系中加入乙烯醋酸乙烯共聚物（ＥＶＡ），其相容性得到改善，力学性能进一步提高。     

由溶致液晶制备高强高模纤维素纤维

工业生产的三醋酯纤维素（分子量约１０＾５）溶解在三氟乙酸（ＴＦＡ）和二氯甲烷（ＣＨ２Ｃｌ２）混合溶剂中，在一定浓度下可形成液晶。选择了不同条件进行液晶纺丝，再把初生纤维经过２３５℃热处理，通过不同皂化处理，得到强度为１１．０２ｃＮ／ｄｔｅｘ，模量为３４８．９８ｃＮ／ｄｔｅｘ的高强高模纤维素纤维。Ｘ－光衍射分析表明该纤维素纤维属于纤维素Ⅰ族。     

刚性聚合物粒子增韧 PVC/ELVALOY 共混体系的研究

ＰＶＣ／ＥＬＶＡＬＯＹ共混物是一类柔韧性良好的新型ＰＶＣ合金,ＥＬＶＡＬＯＹ加入５ｐｈｒ时,ＰＶＣ呈现反增塑行为,以后随ＥＬＶＡＬＯＹ含量的增加,共混物的柔韧性明显提高,本文以其作为韧性基体,再掺入刚性聚合物粒子,如ＰＭＭＡ、ＡＳ、ＰＳ等进一步提高了其韧性,对ＰＶＣ／ＥＬＶＡＬＯＹ（１００／５）体系,ＰＭＭＡ在８ｐｈｒ时,缺口冲击强度的提高达到最大值,屈服强度同时提高,ＰＳ和ＡＳ的加入反倒使冲击强度下降;而ＰＶＣ／ＥＬＶＡＬＯＹ（１００／２０）、体系、ＰＭＭＡ、ＡＳ、ＰＳ均有增韧效应,其中ＡＳ的缺口冲击强度提高最大,达８３％,而其屈服强度基本保持不变．由ＳＥＭ照片,刚性聚合物的冷拉效应亦明显地产生．     

EC、SEV、及CV硫化NR的对比研究

研究了平衡硫化体系（ＥＣ）硫化天然橡胶（ＮＲ）的硫化返原、拉伸性能、撕裂强度、耐磨性、耐屈挠性及生热性随硫化时间的变化，并与半有效硫化体系（ＳＥＶ）及传统硫化体系（ＣＶ）进行了对比。结果表明，ＥＣ硫化ＮＲ的返原作用略高于ＳＥＶ，但明显地低于ＣＶ，硫化６ｈ返原率依次为７．７％、０．４％极３４．０％；与ＳＥＶ及ＣＶ相比，在不同硫化时问下，ＥＣ硫化ＮＲ具有高的拉伸强度、撕裂强度及３００％定伸应力，低的生热性，好的耐磨性和耐屈挠性。对不同硫化体系硫化ＮＲ的化学应力松弛的测定表明，ＥＣ硫化胶的耐热氧老化性优于ＳＥＶ，更优于ＣＶ。     

典型的发泡剂热分解特性的研究

研究了典型的放热型发泡剂ＡＣ （偶氮二甲酰胺）、吸热型发泡剂ＨＹＤＲＯＣＥＲＯＬＢＩＨ （柠檬酸钠和ＮａＨＣＯ３ 复合物） 和吸放热型发泡剂ＥＸＯ－ＣＥＲＯＬ２３２（ＡＣ,ＮａＨＣＯ３, 柠檬酸复合物）分解热力学和动力学特性。用ＤＳＣ差示扫描量热仪测定了动态分解温度、热效应和发泡助剂对分解热力学的影响,并用自行设计的发泡剂分解特性测量装置测定了体系在不同温度下的分解动力学, 详细比较了其优缺点。为新型吸－放热型发泡剂的开发利用和传统发泡剂的改进提供了参考数据     

聚碳酸酯／热致聚酯液晶原位复合材料的结构与性能

向聚碳酸酯（PC）中加入一种半芳族热致液晶聚合物（TLCPA2）,当TLCPA2用量低于10％时,在较低剪切速率区原位复合体系的表现粘度较PC及TLCPA2均有明显的降低,拉伸强度、弯曲强度、拉伸模量、弯曲模量较PC均有提高,当TLCPA2用量加至20％时,复合体系呈圉明显的皮－芯形态,材料的抗拉及抗压强度劣化。     

固相法氯化聚乙烯改性聚氯乙烯的研究

以固相法氯化聚乙烯（ＣＰＥ）改性聚氯乙烯（ＰＶＣ）为研究对象，讨论了ＣＰＥ的用量、ＣＰＥ中的氯含量、ＣＰＥ的氯化温度及氯化方法对改性ＰＶＣ的影响。实验结果表明，ＣＰＥ中氯含量为２７％～４４％用量在１０～１４份范围增韧ＰＶＣ可达到较好的效果。另外，固相氯化法所得ＣＰＥ对ＰＶＣ改性提高了冲击强度，而拉伸强度下降较少。     

工艺参数对注塑压缩PC板力学性能的影响

为了研究模具温度、熔体温度、压缩力等工艺参数对注塑压塑聚碳酸酯制件力学性能的影响,以模拟得到的最优工艺参数组合为参考,采用单因素法制取了聚碳酸酯板,并对其进行了拉伸实验研究．结果表明:聚碳酸酯塑压试件的屈服强度随模具温度的增大而减小,随熔体温度、压缩力、压缩速度的增大而增大;总延伸率随模具温度、压缩力、压缩速度的增大而减小,随熔体温度的增大而增大．     

Effect of TBC plasticization on thin polycarbonate sheet

Tributyl citrate （TBC） plasticizer has been selected to prepare the novel plasticized PC under different time and temperature. The TBC plasticization effect on PC T, mechanical properties and morphology has been investigated by DMTA, DSC, tensile test and SEM. The results show that the TBC content in PC is controlled by plasticization time and temperature. The mass-loss test has conftnned a less lost rate of TBC in PC. The T declines gradually with increasing TBC content. The tensile modulus and strength of the plasticized PC also decrease with the increase of TBC content, and an approximate linear relationship is found to exist between the TBC content and the tensile modulus and strength. The SEM images show that significant changes have taken place on the surface and in the cross-section of plasticized thin PC sheet.     

一种高苯基含量有机硅阻燃聚碳酸酯的研究

以二苯基二甲氧基硅烷为单体合成出八苯基环四硅氧烷(P4),将其作为一种无卤硅系阻燃剂与聚碳酸酯(PC)按比例共混挤出制得无卤阻燃PC。对该无卤阻燃PC样品进行极限氧指数测试、UL-94垂直燃烧测试、扫描电镜(SEM)测试、热失重分析(TGA)、熔融指数(MI)测试和力学性能测试。实验结果表明,P4对PC具有显著的阻燃效果,随着P4用量增加,PC阻燃等级不断提高;P4均与分布在P4中,燃烧后炭层随着P4用量增大逐渐致密;该阻燃PC热稳定性有一定的提高,当P4添加量较高时空气氛围中热失重测试后残炭率显著提升;添加P4的阻燃PC熔指有所上升,分子量有所降低; 该阻燃PC拉伸强度和冲击强度在P4添加量较低时下降时较明显,当P4添加量达至4wt%后,拉伸强度和冲击强度变化很小,而该阻燃PC弯曲强度随着P4添加量增加变化很小。     

树脂增强选择性激光烧结多孔金属件的研究

针对选择性激光烧结(SLS)间接方法成型的金属零件形坯,经脱脂和高温烧结后形成的零件存在大量孔隙和空洞,其致密度和强度都较低,不能满足实际应用要求的问题,采用改性耐高温环氧树脂浸渗零件烧结坯的方法,使多孔金属件致密化,并粘结内部金属网架,提高零件的机械性能.对浸渗烧结坯的拉伸强度的测试和扫描电镜(SEM)以及热失重(TGA)的分析结果表明,浸渗树脂后的烧结坯拉伸强度提高了约4倍;改性环氧树脂和金属网架粘结在一起,形成一个密实的网络结构,致密度大幅提高;零件可在200℃的温度下使用.该方法可以制造注塑模具和功能零件.     

添加剂对石膏型强度的影响

在石膏型中分别添加氧化钙、聚丙烯酰胺、甲基纤维素、玻璃纤维四种添加剂,研究加入添加剂后石膏型在室温下抗拉强度及烘干过程中的抗拉强度变化．分析了烘干过程中石膏型抗拉强度随烘干时间、失水率的变化规律,并与石膏型在微波烘干过程的抗拉强度进行了对比分析．     

高温作用对大掺量粉煤灰混凝土力学性能影响

研究了高温作用对大掺量粉煤灰混凝土(HFCC)立方体力学性能的影响,探讨了不同加热温度、不同粉煤灰掺量与HFCC残余强度的关系.将粉煤灰掺量30%、40%和50%的混凝土立方体试块加热至250,450,550和650℃进行强度测试,并与素混凝土(不掺粉煤灰)试块进行对比.研究结果表明,随着温度升高,HFCC残余抗压、劈裂抗拉强度均出现明显退化,劈裂抗拉强度退化尤为明显;随着粉煤灰的掺入,粉煤灰掺量对强度退化率的影响具有复杂性:高温后HFCC抗压强度退化率均低于普通混凝土强度退化率;劈裂抗拉强度退化率除粉煤灰掺量30%外均低于普通混凝土退化率.在试验基础上建立HFCC高温后立方体残余抗压强度、残余劈裂抗拉强度与温度、粉煤灰掺量的定量关系,为高温后HFCC材料强度评估及修复提供依据.     

Flexural-tensile properties of layered steel fiber reinforced rubber concrete

Layered steel fiber reinforced rubber concrete (LSFRRC), a new type of pavement concrete based on the requirements of national standard were experimentally researched. The different properties of flexural-tensile strength from plain concrete (PC), rubber concrete (RC), layered steel fiber reinforced concrete (LSFRC) and LSFRRC were presented. Experimental results show that the tensile strength of LSFRRC is improved by 4.12% compared with PC, by 13.75% compared with RC. The load-deflection curve on flexural-tensile propertiesis put forward. The flexural-tensile toughness index I10 of LSFRRC is improved 10.32 times compared with PC.     

振动注射实现等规聚丙烯自增强自增韧

利用自行研制的两种振动注射装置，研究振动频率对等规聚丙烯机械性能的影响。振动频率的提高有利于试样屈服强度增加，并存在一个最大值，在强度峰值之后，振动频率的增加使屈服强度的变化不大，但总是大于常规注射得到的屈服强度值；较低的振动频率使断裂伸长率降低，之后振动频率增加有利于断裂伸长率提高；振动频率的增加明显提高冲击强度(对于振动注射Ⅰ，频率大于4．17Hz，冲击强度变化不大)。可见，振动注射可以实现聚丙烯自增强的同时自增韧。     

Effect of carbon fibre on properties of TiB2/C composite cathode coating for aluminum electrolysis

The tensile strength, compressive strength and electrical resistivity of TiB2/C composite cathode coating were measured with a hydraulic pressure universal test machine and an electrical resistivity test device, and the effects of carbon fibre content and carbon fibre length on tensile strength, compressive strength and electrical resistivity were investigated. The results show that the tensile strength of coating increases at the beginning and then reduces with the increase of carbon fibre content when the carbon fibre (length of 3 mm) content ranges from 0 to 4.0%; at the carbon fibre content of 1.5%, the tensile strength of coating reaches the maximum, 25.6 MPa. For the coating with carbon fibre content of 1.5%, the carbon fibre length has a great influence on tensile strength and compressive strength of coating; when the carbon fibre length is 6 mm, the tensile strength and compressive strength of coating reach the maximum, 27.6 MPa and 39.2 MPa, respectively. The electrical resistivity of coating reduces with the rise of temperature and the length of carbon fibre, and the influence of carbon fibre length on electrical resistivity of coating at low temperature (30-200℃) is more obvious than that at high temperature (960℃).     

Microstructure and mechanical properties of CaCO<Subscript>3</Subscript> whisker-reinforced cement

Composite Portland cement (PC) played an important role in various kinds of construction engineering owing to low hydration heat, low-cost, and application of solid industrial waste, but its brittleness and low strength limited its use in stress-bearing locations. The aim of this study is to improve the toughness and fracture resistance by incorporating CaCO₃ whisker in cement matrix. Effect of different content of calcium carbonate whiskers on the mechanical properties of PC was investigated. The results showed that the flexural strength, impact strength and split tensile strength were increased by 39.7%, 39.25% and 36.34% at maximum, respectively. Microstructure and elements of the whiskers in hardened cement were observed and analyzed by SEM/EDS. The mechanisms of the reinforcement of CaCO₃ whisker on cement were also discussed, and the conclusion was that the improvement could be correlated to energy-dissipating processes owing to crack bridging, crack deflection, and whisker pull-out at the crack tips.