聚乙酸乙烯酯和部分水解聚丙烯酰胺在超声波辐照下降解与嵌段共聚的研究

本文分别研究了在超声波辐照作用下聚乙酸乙烯酯(PVAc)和部分水解聚丙烯酰胺(HPAM)在乙醇/水(55/45)中的降解和两者的嵌段共聚反应.结果表明:PVAc的降解速率大致可以用Ovenall方程表示,而HPAM的偏离较大.在25℃、频率为18.2kHz、逆变器主回路输入电流为2.4A的超声强度下,将浓度为0.50%的PVAc/HPAM(1/1)乙醇/水(55/45)溶液辐照10分钟,所得共聚物产率为4.3%.通过溶解试验、电子显微镜、相差显微镜、元素分析、IR和NMR分析了共聚物的结构,证明该共聚物主要为嵌段体.     

聚氧化乙烯和聚丙烯酰胺在高速搅拌下的机械降解

本文分别研究了在高速搅拌下水溶液中聚氧化乙烯(PEO)和聚丙烯酰胺(PAM)的机械降解.在一定浓度范围内极限链长和降解速率常数随浓度变化而变化.在给定浓度下速率常数与搅拌时间有关.每一分子的断链次数对搅拌时间的依赖性可用如下方程描述:B_O=(P_O/P_∞-1)〔1-exp(-K_OP_∞t)exp(1/2K_1P_∞t~2)〕.据实验结果推测:在0.5%的水溶液中,无论PEO或PAM分子可能皆不形成缠结结构.由降解前后聚合物的GPC法分析可知,经降解的聚合物分子量分布变窄.     

淀粉-丙烯酰胺辐照接枝共聚动力学模型研究

研究淀粉与丙烯酰胺在60Coγ射线引发下辐照剂量对接枝聚合率的影响。关联得到通用的接枝反应动力学方程式:-ddyt=kI0.5yexp[0.5BI0.5(1-y)];简化得到动力学方程式:-ddyt=0.0192I0.5y exp[I0.5(1-y)],对比试验显示:试验值与理论值吻合性很好。     

热塑性聚砜-聚二甲基硅氧烷嵌段共聚弹性体的合成

以羟基封端聚砜齐聚物(简称聚砜齐聚物)和二甲胺封端聚二甲基硅氧烷齐聚物(简称聚硅氧烷齐聚物)的缩聚,可得到聚砜-聚二甲基硅氧烷嵌段共聚物。改变两种齐聚物的分子量,可以合成出具有从塑料到橡胶性能的各种嵌段共聚物。     

聚丙烯酰胺降解研究

随着我国石油的大量开采,聚丙烯酰胺作为驱油用聚合物得到广泛使用,含聚丙烯酰胺的油田污水在逐年增加,聚丙烯酰胺增加污水的黏度和乳化性,使得采出水油量严重超标,对环境造成很大负面影响。通过氧化反应与光催化反应对聚丙烯酰胺进行降解,使得采出水聚合物大量减少。通过对Fenton法和光催化反应中不同因素的影响进行实验,得出最佳反应条件,使聚丙烯酰胺降解率得到提高。本文的研究对实践减少采出水聚合物有重要意义。     

含聚氧化乙烯嵌段的二元多嵌段共聚物的合成和性能

用遥爪羟基聚苯乙烯与聚乙二醇和二氯甲烷在氢氧化钾存在下合成了氧亚甲基连接的聚氧乙烯 -聚苯乙烯多嵌段共聚物 ,采用FT -IR、1HNMR、分子量测定和凝胶渗透色谱分析表征共聚物的结构 ,研究了共聚物的乳化性能和相转移催化性能。结果表明 ,该类共聚物具有较好的乳化性能和相转移催化性能     

含聚氧化乙烯嵌段的二元多嵌段共聚物的合成和性能

用遥爪羟基聚苯乙烯与聚乙二醇和二氯甲烷在氢氧化钾存在下合成了氧亚甲基连接的聚氧乙烯－聚苯乙烯多嵌段共聚物，采用FT－IR、^1HNMR，分子量测定和凝胶渗透色谱分析表征共聚物的结构，研究了共聚物的乳化性能和相转移催化性能，结果表明，该类共聚物具有较好的乳化性能和相转移催化性能。     

共聚共混聚酯-聚醚嵌段共聚物的研究

将聚对苯二甲酸乙二酯-聚四亚甲基醚(PET-PTMG)嵌段共聚物中共混少量聚对苯二甲酸丁二酯-聚四亚甲基醚(PBT-PTMG),或在PET-PTMG合成中加入一定量丁二醇形成硬链段共聚酯,则相应的共混物或共聚物的结晶速度提高。本工作采用光学解偏振仪及小角激光散射方法研究了上述产物的结晶过程。     

丙烯酰胺-丙烯酸钠水溶液共聚法合成超高分子量聚丙烯酰胺的研究

采用新型氧化还原引发体系,以丙烯酰胺（AM）和丙烯酸（AA）为单体进行水溶液自由基共聚合。合成了分子量高达2．014×107,水解度26．3％,过滤比13．5的超高分子量聚丙烯酰胺。并研究了pH值、引发剂用量、单体总浓度对聚丙烯酰胺分子量的影响,通过正交实验确定了合成超高分子量聚丙烯酰胺的最佳工艺条件。     

共聚法制备高分子聚丙烯酰胺的研究

以氧化还原引发体系为主,配合其它引发剂组成新型复合引发体系。在低温条件下采用水溶液聚合法引发丙烯酰胺和丙烯酸共聚工艺路线制备高分子量聚丙烯酰胺。考查各项因素对聚合反应的影响,最终确定最优化工艺条件：单体浓度0．0035mol／g,氧化还原引发剂14mg／L,EDTA10mg／L,偶氮35mg／L,体系温度0℃,pH值7．0,聚合物分子量为1．943×10^7。     

Chemical Degradation of Poly(Ethylene Terephthalate)

The possibility of converting polyethylene terephthalate (PET) waste into terephthalic acid as a primary material by using different techniques through trans-esterification, with an alcohol and through hydrolysis in basic medium, has been investigated. In addition, utilization of activating agents such as inorganic salts and phase transfer catalysts has been investigated.Mineral water and beverage bottles were collected, cleaned and crushed into flakes suitable for the intended experiments. Also, the main products of chemical conversion of such wastes were isolated and confirmed by authentication with standard terephthalic acid through Thin Layer Chromatography (TLC) technique. The reaction yield % was determined to optimize the corresponding experimental conditions and the obtained results have been presented and discussed.     

Comparison of Poly(Ethylene Oxide) Melt Crystallization in Blend and Block Copolymer Systems with Poly (Methyl Methacrylate) and Poly (Tert-Butyl Methacrylate)

DSC investigations are reported for a broad assortment of blends and copolymers of the immiscible poly(ethylene oxide) (PEO)/poly(tert-butyl) methacrylate) (PTBMA) system. Contrary to expectations, the PEO crystallization and melting behavior of the copolymer system is similar to that of the PEO/poly(methyl methacrylate) (PMMA) copolymer system (which is usually considered to be miscible in the melt). This is discussed with the concept of a UCST-type granulated demixing in the latter. In both systems the crystallization is rather sensitive to the block structure, even for comparable molecular weights and compositions. This indicates some importance of DSC as an additional tool in copolymer characterization. Free PEO ends favor the crystallization in all cases.     

环氧乙烷、环氧丙烷共聚合反应动力学研究

The copolymerization kinetics of ethylene oxide and propylene oxide in an atomizing-circulation reactor under semi-continuous operation is studied which is of great importance for molecular designation.The kinetic parameters are obtained by numerical optimization of the kinetic model.     

在超声波辐照下甲基纤维素的降解及与丙烯腈共聚反应的研究

本文研究了水溶液中甲基纤维素的超声波辐照降解反应,证实该反应具有一般的力降解特征,发现降解速率不是辐照时间的单调增函数.以水/甲酸为溶剂,在超声波辐照下制得了甲基纤维素-丙烯腈共聚物,考察了共聚过程,提供了获得水溶性共聚物的反应条件.证实所得共聚物是接枝,嵌段兼有的共聚物,共聚点主要发生在甲氧基上,共聚物是非晶态的.初步研究了共聚产物水溶液的热稳定性和抗盐性,与甲基纤维素对比,这些性能均有改善.     

Block Copolymers of Ethylene Oxide and Styrene Oxide.New Copolymer Surfactants（ Ⅱ ）.

3.2. Association Number Figure 5 shows the dependence of the weight-average association number (Nw,measured by static light scattering, solution temperature 30 °C) on hydrophobe block length for ES and ESEblock copolymers.     

Block Copolymesrs of Ethylene Oxide and Styrene Oxide. New Copolymer Surfactants(Ⅱ)

~~Block Copolymesrs of Ethylene Oxide and Styrene Oxide. New Copolymer Surfactants(Ⅱ)@David Attwood$School of Pharmacy and Pharmaceutical Science,University of Manchester!Manchester M139PL,U K @Colin Booth$Departmentof Chemistry,U niversity of Manchester!Manchester M139PL,U K.~~…     

Hyperbranched Poly(Glycidol)-Grafted Silica Nanoparticles for Enhancing Li-Ion Conductivity of Poly(Ethylene Oxide)

Silica nanoparticles bearing hyperbranched polyglycidol (hbP) grafts are synthesized and blended with poly(ethylene oxide) (PEO) for the fabrication of composite solid polymer electrolytes (SPEs) for enhancing Li-ion conductivity. Different batches of hbPs are prepared, namely, the 5th, 6th, and 7th with increasing molecular weights using cationic ring-opening polymerization and grafted the hbPs onto the silica nanoparticles using quaternization reaction. The effect of end functionalization of hbP-grafted silica nanoparticles with a nitrile functional group (CN–hbP–SiO₂) on the ionic conductivity of the blends with PEO is further studied. High dipole moments indicate polar nature of nitriles and show high dielectric constants. Among all the hbPs, the 6th-batch CN–hbP–SiO₂ nanoparticles exhibit better ionic conductivity on blending with PEO showing ionic conductivity of 2.3 × 10⁻³ S cm⁻¹ at 80 °C. The blends show electrochemical stability up to 4.5 V versus lithium metal.     

Thermal Degradation Studies of Poly (Amide-Ester)s

Abstract

The thermal behaviour of poly(amide-ester)s with the amide group in the side chain was studied. Polymers were sinthesized from the diphenol-amides N-(2,6-dichloro-4-nitrophenyl)-2, 2-bis(4-hydroxyphenyl)-propanamide, N-(2, 6-dichloro-4-nitrophenyl)-3,3-bis(4-hydroxyphenyl)-butanamide, and N-(2,6-dichloro-4-nitrophenyl)-4, 4-bis(4-hydroxyphenyl)-pentanamide and terephthaloyl chloride, isophthaloyl chloride and adipoyl chloride under phase-transfer conditions using several phase-transfer catalysts. The thermal decomposition temperature was influenced by both, the nature of the diacid and the length of the side chain, those derived from terephthaloyl chloride being more stable than those derived from isophthaloyl chloride and adipoyl chloride. All polymers degrade in a single-step process and the kinetics parameters were determined using the Arrhenius relationship and a computer program.