导热填料对LLDPE性能的影响

选取铝粉(Al)、碳化硅(Si C)、氮化铝(Al N)、氧化镁(Mg O)、石墨(C)和线型低密度聚乙烯(LLDPE),通过注塑成型制备了导热复合材料。研究了导热填料用量对复合材料热导率和力学性能的影响。结果表明:随着导热填料用量的增加,复合材料的热导率明显提高;导热填料用量为9%时,LLDPE/Al和LLDPE/C的导热性能最佳;复合材料的断裂伸长率随着填料用量的增加而下降,石墨(C)加入后基体的拉伸强度上升,其他填料加入后拉伸强度随着填料用量的增加而下降。实验数据表明,复合材料的热导率上升趋势与理论模型的预测趋势一致。     

PE-LLD/SBS共混过程中浓度分布的数值模拟及实验研究

使用POLYFLOW软件对HAAKE混合器中PE-LLD/SBS体系共混过程进行了三维等温数值模拟。通过对混合器位置、转子转速、分散相比例和温度等因素的分析,研究了PE-LLD/SBS熔体在HAAKE混合器中SBS相浓度随时间的分布的规律。并通过实验对模拟结果进行验证,结果表明数值模拟与实验结果有较好的吻合。     

导热SiC/LLDPE复合塑料制备及性能研究

采用碳化硅(SiC)和线性低密度聚乙烯(LLDPE)粒子经粉末混合和热压成型制得导热复合塑料.研究了SiC粒子含量时LLDPE熔融温度、结晶度、热导率、介电及力学性能的影响.结果表明:SiC粒子降低了LLDPE结晶度,对熔融温度元明显影响;随SiC含量增加,热导率升高,介电常数和损耗升高,但仍然保持在较低数值,而力学性能下降.     

The Effect of the Nano-ZnO Concentration on the Mechanical,Antibacterial and Melt Rheological Properties of LLDPE/Modified Nano-ZnO Composite Films

LLDPE/modified nano-ZnO composite films were prepared using LLDPE and KH550-modified nano-ZnO by melt blending and blowing. The research results indicated that the introduction of the modified nano-ZnO improved the mechanical properties of the LLDPE films, the maximum tensile strength and elongation at break were obtained at modified nano-ZnO content of 0.3 wt%. The composite films exhibited favorable antibacterial activity against Escherichia coli and Staphylococcus aureus. The low doped content of modified nano-ZnO in LLDPE matrix made the melt viscosity of the composites increase slightly, it was coincident with variation of the balance torque with the nano-ZnO content.     

过氧化氢分解热的测定实验的改进

磁力搅拌器可随意调控搅拌速度,与裸露在外的搅拌棒相比,搅拌时不会造成系统热量的流失;精密温度传感器具有灵敏度高、数据显示直观的优点,所测数据可以实时传输到计算机中,便于微机处理。二者配合使用可提高实验的准确性与自动化程度。不仅如此,其更大的意义在于,能将该项目改进为演示实验,方便学生通过计算机进行预习与自学。     

高聚物热性能的测试与分析综合性实验设计

设计了《高分子物理课程》下的高聚物热性能的测试与分析综合性实验,利用同步热分析仪(TGA/DSC)和差示扫描量热仪(DSC)测试了多种高聚物受热后性能的变化,扩展了实验内容;通过分析测试图谱,进一步了解高聚物的结构与性能之间的关系,使学生在熟悉仪器操作的同时,掌握热分析测试的原理,并对测试数据进行处理和分析,学会从数据中得出性能的综合分析能力。     

过氧化二异丙苯用量对三元乙丙橡胶性能的影响

通过机械共混法制备三元乙丙橡胶(EPDM)胶料,研究过氧化二异丙苯(DCP)用量对EPDM胶料硫化特性、物理性能和润湿性能的影响。结果表明:随着DCP用量增大,混炼胶的硫化时间呈缩短趋势;硫化胶的硬度、拉伸强度、拉断伸长率和润湿角呈先增大后减小趋势;当DCP用量为3份时,硫化胶的综合物理性能最佳,与水的亲和力最弱。     

Effect of the Incorporation of PVC on the Mechanical Properties of the Jute-Reinforced LLDPE Composite

Jute fabrics-reinforced linear low density polyethylene (LLDPE) matrix composites (50 wt% fiber) were prepared by compression molding and mechanical properties were studied. Polyvinyl chloride (PVC) matrix was incorporated instead of LLDPE in the jute based composites and their mechanical properties were investigated and compared with the control composites. It was found that with the increase of PVC in the LLDPE based composites, the mechanical properties were found to improve significantly. Degradation tests of the composites for upto 24 weeks were performed in soil medium. Water uptake and Thermo-mechanical properties of the composites were also studied.     

纳米SiO2对PP/LLDPE共混体系结构与性能的影响

将纳米二氧化硅(nano-Si O2)按不同比例加入到聚丙烯(PP)/线型低密度聚乙烯(LLDPE)体系中制备PP/LLDPE/nano-Si O2复合材料。采用X射线衍射仪、扫描电子显微镜、差热扫描量热法以及力学性能测试等手段研究了nano-Si O2对PP/LLDPE复合体系微观结构和力学性能的影响。结果表明,在PP/LLDPE/nano-Si O2复合体系中,随着nano-Si O2分散性的提高,可促使PP与LLDPE之间相互作用增强,PP球晶细化,复合材料的力学性能明显提高。当nano-Si O2的含量在1%时,纳米粒子在基体中分散均匀,冲击强度和拉伸强度分别较纯样提高了28.2%和2%。     

Explosive Properties and Thermal Stability of Urea‐Hydrogen Peroxide Adduct

The adduct of urea and hydrogen peroxide (UHP) is industrially produced material on a large scale. Although UHP is widely used as a bleaching and oxidizing agent, its properties as energetic material are generally overlooked. In this work we report comprehensive characterization of UHP explosive and thermal properties. We found that UHP is a compound with a negative value of standard enthalpy of formation (−565.1 kJ mol⁻¹). It is not sensitive to impact and friction. However, we demonstrated that UHP (ρ =0.93 g cm⁻³; packed into a steel pipe with inner diameter of 206 mm) detonates with experimental velocity of detonation (VOD) of 3780 m s⁻¹. Moreover, for UHP with maximal theoretical density (ρ =1.43 g cm⁻³), the calculated VOD reaches 5219 m s⁻¹. Based on our findings, we recommend that present regulations regarding the handling, storage and transportation of the UHP should be revised, especially in cases, where UHP is kept on a large scale, under confinement and at places where the temperature can reach above 60 °C.     

Chemical Modification of Chitosan-Filled Polypropylene (PP) Composites: The Effect of 3-Aminopropyltriethoxysilane on Mechanical and Thermal Properties

Chitosan was used as filler in polypropylene (PP) polymer. In order to improve compatibility between chitosan and PP, chitosan was chemically modified with 3-aminopropyltriethoxysilane (3-APE). The results show that the increasing of filler content decreased tensile strength and elongation at break, but increased Young's modulus of composites. The treated composites exhibit higher tensile strength and Young's modulus, but lower elongation at break compared untreated composites. The addition of 3-APE has improved thermal properties such as thermal stability and crystallinity of treated composites. SEM study of the tensile fracture surface of treated composites shows better interfacial interaction and adhesion between the chitosan-PP matrix.     

木粉对LLDPE膨胀阻燃体系热降解和阻燃的影响

以木粉部分或完全代替季戊四醇作为膨胀型阻燃剂的碳源,研究木粉的加入对LLDPE膨胀阻燃体系热降解和阻燃性的影响.研究表明:木粉对膨胀体系的热降解行为影响不大,当木粉在成炭剂中的质量含量为20%时,膨胀体系的阻燃效果最好.     

基于热分析的LLDPE与LDPE鉴别方法研究

海关进出口税则中规定线性低密度聚乙烯关税税率为6．5％;低密度聚乙烯关税税率为10．3％。两者外观相似而价格和税率都相差较大。用通常的红外分析方法很难区分二者,本文从差热分析方法入手,对二者进行了研究,制定了适合海关实际操作的鉴别方法。结果表明,该方法简便、准确,在实际应用中能获得满意的效果。     

共混改性国产LLDPE泡沫塑料的研究

本研究采用一步法模压发泡工艺,分别选用ＥＬＶＡＬＯＹ７４１及不同型号的ＥＶＡ与ＬＬＤＰＥ进行共混改性,并探讨了不同用量ＥＬＶＡＬＯＹ７４１和不同型号的ＥＶＡ对泡沫塑料性能的影响．并观察了泡沫塑料的微观结构．     

改善建筑陶瓷墙地砖强度和导热性能的试验研究

以粘土、煅烧高岭土、长石、锂辉石和煅烧氧化铝等为原料,采用半干压法压制成型,在1210～1220℃温度范围内烧成,研制了具有较高体积密度、抗压强度和导热系数的新型陶瓷墙地砖。实验研究结果表明,通过优化现有陶瓷墙地砖的工艺配方,改善陶瓷墙地砖微观结构,有利于降低陶瓷墙地砖的气孔率,提高陶瓷墙地砖的致密度和刚玉-莫来石相含量,可获得导热系数为2.0～2.4W/(m.K)、断裂模数为51～57MPa的新型陶瓷墙地砖。     

Effect of Polymer Concentration on Autoclaved Cryogel Properties

Biomaterial sterilization is a prerequisite prior to patient's use, especially for scaffold implantation or injection. Various sterilization processes are mandated by the Food and Drug Administration including high‐pressure steam sterilization. Although high‐pressure steam or autoclave sterilization eliminates pathogens, it often leads to irreversible damages on soft materials such as hydrogels. In the current study, the impact of autoclave sterilization on cryogels made from several naturally‐derived polymeric precursors (alginate, hyaluronic acid, and gelatin) is analyzed. Specifically, the impact of polymer concentration on the structural and physical properties of autoclaved cryogels such as mechanics, swelling ratio, pore interconnectivity, and shape‐memory features is studied. The results demonstrate that at a given optimal polymer concentration, unique for each biopolymer investigated, autoclave sterilization does not substantially alter the microarchitectural or physical characteristics of cryogels, including their syringe injectability signature. In summary, when formulated under optimized polymer concentrations, autoclavable cryogels hold great potential for several biomedical applications, as they can be easily translated into clinical practice to benefit public health.     

过氧化物晶体的制备及晶体性能研究

过氧化物晶体具有低声子能量,极高的热导率和破坏阈值,是优异的中红外固体激光基质,然而由于熔点高,激光晶体极难生长.本文以热交换法为晶体生长方法,研究过氧化物晶体的生长,并对过氧化物晶体的性能进行了初步研究.