Hexagonal columnar mesophases of polycatenar para-phenylene connected bis-oxadiazole-based liquid crystals

In this article polycatenar liquid crystals containing two 1,3,4-oxadiazoles interconnected by a para-substituted benzene ring as the central linking unit and three alkoxy chains at each terminal have been synthesised, and investigated by polarising microscopy, DSC and XRD scattering. Molecules with medium chain length form exclusively hexagonal columnar liquid crystalline phases.     

Surfactant-free cellulose filaments stabilized oil in water emulsions

Cellulose - There has been significant interest over recent years in the production and application of sustainable and green materials. Among these, nanocellulose has incurred great interest...     

钯纳米微粒的微波高压液相合成及共振散射光谱研究

以柠檬酸钠作为制备钯纳米微粒晶种的还原剂,聚丙烯酰胺作为晶种生长的还原剂和稳定剂,采用微波高压液相合成法制备液相钯纳米粒子。TEM表明,钯纳米粒子呈球形,通过改变柠檬酸钠浓度可获得粒径为6－76nm的钯纳米粒子。柠檬酸在216nm处有一个吸收峰。聚丙烯酰胺在205nm处有一个吸收峰。钯纳米粒子体系在紫外可见光波长范围内无吸收峰,随着波长的降低其吸收增大。粒径为6－76nm的低浓度钯纳米粒子均在470nm、510nm、400nm、800nm和940nm产生五个共振散射峰。     

聚氯乙烯／线性低密度聚乙烯共混体系的相容性

用动态力学分析（ＤＭＡ）和傅利叶变换红外光谱（ＦＴＩＲ）研究了氢化聚丁二烯－ｂ－聚甲基丙烯酸甲酯（ＨＰＢＤ－ｂ－ＰＭＭＡ）共聚物增容剂对聚氯乙烯（ＰＶＣ）与线性低密度聚乙烯（ＬＬＤＰＥ）共混体系的增容作用．增容剂使共混物中两相的玻璃化温度发生变化，说明其相容性增加．ＦＴＩＲ的结果表明，增容剂中羰基与ＰＶＣ的α氢形成氢键，使ＣＯ，Ｈ─Ｃ及Ｃ─Ｃｌ的振动频率变化，峰形加宽．     

PVC/PBD-b-PMMA共混体系相容性的研究

采用ＤＭＡ和ＴＥＭ系统研究了聚丁二烯－聚甲基丙烯酸甲酯的嵌段共聚物（ＰＢＤ－ｂ－ＰＭＭＡ）与聚氯乙烯（ＰＶＣ）共混体系的相容性问题。结果表明：ＰＶＣ／ＰＢＤ－ｂ－ＰＭＭＡ共混体系具有部分相溶性。相容的程度与共混体系的组成、组分聚合物的分子量以及共聚物中ＰＢＤ和ＰＭＭＡ嵌段的比例密切相关。     

聚氯乙烯—丁腈橡胶—氯丁橡胶三元共混物的研究

测定了聚氯乙烯（ＰＶＣ）－丁脯橡胶（ＮＢＲ－２９）－氯丁橡胶（ＣＲ）三元共混物的冲击性能和应力－应变行为，用动态力分析、扫描电和透射电镜研究了共混物的相容性和形态结构。结果表明，ＮＢＲ－２９对ＰＶＣ，ＣＲ有良好的增容作用，三元共混物是部分相容的二相体系，具有良好的抗冲击性能。     

Infinitely many homoclinic solutions for second order Hamiltonian systems

In this paper we study the existence of infinitely many homoclinic solutions for second order Hamiltonian systems , , where L(t) is unnecessarily positive definite for all t∈R, and W(t,u) is of subquadratic growth as |u|→∞.     

丁二烯－甲基丙烯酸甲酯嵌段共聚物的阴离子聚合及表征

讨论了用阴离子方法进行了二烯与甲基丙烯酸甲酯共聚合的过程，并用ＧＰＣ、ＦＴＩＲ、ＮＭＲ和动态粘弹谱对共聚物进行了表征．证明所得聚合物为具有较高分子量、窄分布的二嵌段共聚物．