Effect of the ionic composition of the solution on the polyvinyl alcohol adsorption on the surface of al2o3

The adsorption of polyvinyl alcohol (PVA) from solutions of various ionic composition has been studied on alumina. In the presence of sodium dedecylsulphate (SDS) the complexes PVA-SDS are probably formed at the interface oxide-solution. The interacaction between PVA and SDS at the interface leads to increase of PVA adsorption. However the presence of such complexes in the solution causes stepwise decrease of polyvinyl alcohol adsorption. The observed changes of surface charge density of alumina are in accord with the adsorption data. The estimated free energy of PVA adsorption on the surface of alumina is less than −9.7kJ/mole.     

基于ISIGHT的安全气囊盖板结构优化设计方法研究

选取某款弱化沟槽呈“H”形的聚碳酸酯/丙烯腈?丁二烯?苯乙烯共聚物(PC/ABS)合金材质安全气囊盖板为研究对象,并构建了其有限元仿真模型,对比有限元力学仿真分析结果与理论计算值验证了该有限元仿真模型的可靠性;通过ISIGHT软件集成Catia和ANSYS,选取安全气囊盖板弱化沟槽的横向长度、深度,纵向长度、深度4个参数作为设计变量,选取弱化沟槽横向最大应力与纵向最大应力作为响应变量,分析了设计变量对响应变量的贡献度分布特征并采用NSGA遗传算法对响应变量多目标优化。结果表明,横向长度、纵向深度对横向最大应力为负贡献度,横向深度、纵向长度为正贡献度;横向深度、纵向长度对纵向最大应力为负贡献度,横向长度、纵向深度为正贡献度;在合理范围内,4个参数值的优化设计,实现了横向最大应力提高和纵向最大应力降低的多目标优化,有效减少了安全气囊盖板爆破时产生的碎屑量,提升了产品的安全性能。     

Isothermal melt crystallization and performance evaluation of polylactide/thermoplastic polyester blends with multi‐functional epoxy

A multi‐functional epoxy (ADR) was used to improve compatibilization of poly(lactic acid) (PLA)/ thermoplastic polyester elastomer (TPEE) blends. Influence of ADR on isothermal melt crystallization of the blends was investigated. The results show that isothermal melt crystallization rate of the samples increases with ADR loading. It can be attributed to a nucleation enhancement resulted from an increase of molecular weight and melt viscosity created by the chain extension/branched process of PLA in the presence of ADR. In addition, the maximum crystallinity of the samples shows a decrease with increasing ADR loading because of the chain extended and branched reaction. Quenched and crystallized samples were fabricated using compression molding under different cooling conditions in‐mold. Effects of crystallinity and ADR on mechanical performances of the PLA/TPEE sample were investigated. With increasing the crystallinity, the PLA/TPEE sample shows a marked enhancement in heat resistance. However, the tensile ductility of the crystallized PLA/TPEE sample drastically decreases due to the formation of firm crystal crosslinking and the incompatibility between PLA and TPEE. It is notable that the tensile ductility of the crystallized samples is improved with the introduction of ADR owing to its reactive compatibilization effect. Finally, the crystallized PLA/TPEE/ADR samples with improved heat resistance and relative higher ductility are obtained. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46343.     

两种甲酯化法比较微波辅助及超临界CO2提取琼榄果实油的成分

以南药琼榄果实为原料,采用微波辅助提取法(MAE)和超临界CO2提取法(SFE-CO2)提取琼榄果实油,并用气-质联用仪(GC-MS)比较了琼榄油经碱催化和BF3-MeOH催化甲酯化后的脂肪酸成分及其相对质量分数。结果表明,两种方法所提取琼榄油的脂肪酸成分大致相同。GC-MS分析MAE(碱催化法)、SFE-CO2(碱催化法)、MAE(BF3-MeOH催化法)、SFE-CO2(BF3-MeOH催化法)这4种方法所得的琼榄果实油,其中相对质量分数最高的是十八碳烯酸(69.44%、69.04%、64.92%、64.69%),次之为棕榈酸(20.82%、21.01%、21.45%、21.70%),再次是亚油酸(6.33%、6.03%、6.33%、6.13%)。不饱和脂肪酸占脂肪酸总量分别高达76.75%、75.91%、74.77%、74.30%。     

不同热解温度下禾本科植物生物炭理化特性分析

以禾本科植物王草、水稻秸秆、甘蔗渣和玉米秸秆为原料,在厌氧条件下于300、500和700℃制备王草炭(I)、水稻秸秆炭(R)、甘蔗渣炭(S)和玉米秸秆炭(M),研究了不同热解温度对生物炭结构及组成的影响.研究结果表明:随着热解温度升高,4种生物炭产率下降,300℃时I、R、S和M的产率分别为45.81％、48.67％、...     

初始成分对梯度硬质合金微观组织及脱β层厚度的影响

采用普通市售中颗粒Ti(C,N)粉末,以一步烧结法制备脱β层梯度硬质合金;利用显微组织分析和图像分析等手段,研究合金初始成分对其微观组织及脱β层厚度的影响规律。结果表明:当Ti(C,N)含量低于1.6%(质量分数)时,随着Ti(C,N)含量的增加,脱β层厚度明显增大,而当Ti(C,N)含量超过1.6%时,脱β层厚度呈缓慢缩小的趋势;随着钴含量的增加,脱β层的厚度迅速增大,但当钴含量达到10%(质量分数)左右时,在脱β层与芯部的界面处钴相聚集现象严重;总碳含量为6.51%(质量分数)的合金中WC晶粒度较大且呈规则的多边形,在1 450℃、2 h梯度烧结工艺下制备的脱β层厚度可达38μm左右,而总碳含量为6.23%的合金中WC晶粒度较小且呈等轴化趋势,同时脱β层的厚度仅为17μm左右。     

5-氨基间苯二甲酸与乙酸铜或乙酸钴的机械化学反应研究

采用振荡式球磨机作为机械能发生装置,分别研究了5-氨基间苯二甲酸(H2AIP)和乙酸铜或乙酸钴的机械化学反应。结果表明,当在振荡式球磨机(20 Hz)中球磨30 min促使生成2维聚合物:[Cu(HAIP)2]H2O和[Co(HAIP)2(H2O)2]2H2O。     

油酸钠/十二烷基麦芽糖苷混合体系溶液的聚集行为

通过表面张力法和荧光探针法研究了阴离子表面活性剂油酸钠(NaOA)与非离子表面活性剂n-十二烷基-β-D-麦芽糖苷(DDM)组成的二元混合体系分别在水和体积分数为20%的乙二醇水溶液中的聚集行为。利用Rubingh模型和Maeda模型得到的相互作用结果一致,表明NaOA/DDM混合体系在水和20%的乙二醇水溶液中均存在协同效应,在NaOA摩尔分数达到0.4时,混合体系的协同效应均达到最强。乙二醇的加入增大了混合体系的临界胶束浓度,降低了表面活性剂的吸附效率。荧光测试结果表明,乙二醇能够破坏胶束结构,减小胶束聚集数,增加微环境极性。     

不同配方对改性废胶粉性能的影响

研究了不同配方改性胶粉的硫化特性和物理机械性能;考察了活化剂420的用量、三乙醇胺的用量、软化剂丙烯酸的用量对改性胶粉的性能影响。结果表明：将几种活化剂、软化剂并用改性胶粉,所得胶样的性能较好。