星形高乙烯基聚丁二烯微观结构的控制研究

采用多官能度有机锂引发剂一步法合成星形高乙烯基聚丁二烯，结果表明极性调节剂及反应温度是影响聚合物微观结构的主要因素，聚合物的平均臂数越多，星形高乙烯基聚丁二烯的相对分子质量分布越窄。     

负离子法合成端羟基聚丁二烯中极性添加剂的研究

在负离子法合成端羟基聚丁二烯过程中加入了极性添加剂(YB),有效地控制了活性短链引发剂和试样的相对分子质量及其分布,提高了其平均官能度。     

线型及星形端羟基聚丁二烯的合成与表征

以叔丁基二甲基硅氧基丙基锂为引发剂,丁二烯为单体,环己烷为溶剂,甲基三氯硅烷为偶联剂,采用活性负离子聚合法合成了线型端羟基聚丁二烯(L-HTPB)和星形端羟基聚丁二烯(S-HTPB),并用凝胶渗透色谱和核磁共振氢谱对其结构进行了表征。结果表明,采用该方法合成的2种聚丁二烯,其1,4-结构摩尔分数均接近90.00%,L-HTPB的平均官能度接近2.00,S-HTPB的平均官能度接近3.00,与分子设计值基本相符。     

端羟基聚丁二烯官能度对推进剂力学性能的影响研究

通过凝胶渗透色谱（GPC）测定端羟基聚丁二烯（HTPB）样品的平均相对分子质量,化学滴定测定样品羟值,根据相对分子质量和羟值计算得到产品的平均官能度。通过假设交联密度和交联点间相对分子质量分别与推进剂抗拉强度和延伸率成正比,建立简单的官能度数学模型,阐述了平均官能度对推进剂力学性能的影响,同时官能度变化可很好地解释HTPB推进剂固化“活性”的差异。     

端胺基聚丁二烯的合成与表征

采用阴离子聚合法合成了端羟基聚丁二烯,通过端基转化法将羟基转化成胺基,从而合成了端胺基聚丁二烯,通过红外光谱（IR）、核磁共振（1H-NMR）、凝胶渗透色谱（GPC）等对其进行了表征。结果表明,所合成的端胺基聚丁二烯相对分子质量分布较窄（≤1.10）,平均官能度接近2,且微观结构可调;通过羟基值与胺基值的测定表明,端基转化率大于98%。     

阴离子端羟基聚丁二烯的表征及其固化物的力学性能

简述了以硅烷保护羟基的烷基锂为引发剂,环己烷为溶剂合成丁羟胶的聚合方法;通过IR、^1H—NMR和GPC等方法研究了阴离子端羟基聚丁二烯主链结构、分子质量分布、官能度及其分布;对其固化物力学性能进行了评价。研究结果表明,阴离子端羟基聚丁二烯的1,4-结构含量高达约90％、分子质量分布指数≤1．05、官能度接近2,其固化物具有优异的力学性能。     

以齐聚异戊二烯二锂为引发剂制备端羟基聚丁二烯的研究

本工作研究了锂-萘-四氢呋喃引发体系合成的α,ω-端羟基聚丁二烯的特性,以及聚合反应条件对聚合物微观结构、分子量分布、端羟基平均官能度等的影响。实验结果表明,合成的引发剂平均官能度 f 接近2,聚合度 n 为1—7。用此引发剂合成的聚丁二烯,分子量M_n 认为2—5×10~3,1,2结构含量约为50％;分子量分布较窄。当引发剂浓度为47—119毫摩尔/100克单体时,聚丁二烯中1,2结构含量基本不变,但当引发剂浓度大幅度下降时,则1,2结构含量也随之下降。     

GPC法测定HTPB的官能度分布

端羟基聚丁二烯(HTPB)是一种重要的预聚物。据报道,HTPB的分子量(Mi)、分子量分布、官能度(f)和官能度分布对其物理和加工性能均有很大的影响。因此,对HTPB官能度分布的研究,具有十分重要的意义。 HTPB在聚合过程中,由于无法控制链的转移而产生了不同的官能度。预聚物的官能度被定义为预聚物的数均分子量(Mn)     

含不同臂数星形 SIBR的合成

以多官能团锂为引发剂，一步法合成了含不同臂数的星形SIBR，研究了他们的序列结构、相对分子质量及其分布，以及物理机械性能。；结果表明，调节引发剂的官能能度可控制聚合物的臂数，进而得到性能优良的SIBR。     

端羟基聚丁二烯官能度分布的测定

本工作采用高压液相色谱法测定端羟基聚丁二烯(HTPB)的官能度分布.将3,5-二硝基苯甲酰氯(DNBC)在一定条件下,进行衍生化反应.衍生化后的 HTPB 经高压液相色谱仪的紫外(UV)和方差(RI)双检测器进行检测。所得色谱图经数据处理,并分区统计组合,得到 HTPB的羟基官能团随分子量的分布,同时得到相应的数均分子量、重均分子量、分子量分散指数、数均官能度、重均官能度及官能度分散指数.     

Synthesis of star-shaped PCL-b-PMMA/PSt from cyclotriphosphazene initiator by ring-opening polymerization and atom transfer radical polymerization

Summary Star-shaped block copolymers PCL-b-PMMA and PCL-b-PSt were successfully synthesized by ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP) on the basis of hydroxyl-terminated cyclotriphosphazene. The star-shaped PCL was synthesized by bulk polymerization of ε-caprolactone with hydroxyl-terminated cyclotriphosphazene initiator. Star-shaped PCL was converted into a macroinitiator via esterification with 2-bromopropionyl bromide. Star-shaped block copolymers could be obtained by ATRP of methacrylate (MMA) and styrene (St). The molecular weight of these star-shaped block copolymers could be adjusted by the variation of monomer conversion.     

星形PLA-HTPB聚氨酯共聚物的合成与表征

采用自制的星形聚乳酸(PLA)和端羟基聚丁二烯(HTPB)为主要原料,甲苯-2,4-二异氰酸酯为扩链剂合成了星形PLA-HTPB聚氨酯共聚物,通过FT-IR、DSC、TG等测试手段对此共聚物的结构与性能进行表征。结果表明,星形PLA-HTPB聚氨酯共聚物两相具有各自的玻璃化转变温度,两相之间存在相分离现象;其热分解过程为2步,乳酸链段的起始热分解温度为229℃,表观活化能为83.11kJ/mol,反应为一级反应;丁二烯链段的起始热分解温度为414℃,表观活化能为192.83kJ/mol,反应为非一级反应。     

阴离子法丁羟的合成及其微观结构控制研究

以（CH3）3CSi（CH3）2O（CH2）3Li为引发剂，采用阴离子聚合法合成了丁羟胶，通过核磁共振对其进行了表征，并研究了引发剂浓度、单体浓度、极性添加剂四氢呋喃等对聚合物微观结构的影响，并分析了极性添加剂对其微观结构的影响机理。结果表明，引发剂浓度、单体浓度等对丁羟的微观结构影响甚微，而通过调节极性添加剂四氢呋喃的用量可控制丁羟胶的主链微观结构。     

Polymerization kinetics in propellants of the hydroxyl-terminated polybutadiene–isophorone diisocyanate system

The copolymerization of a hydroxyl-terminated polybutadiene with isophorone diisocyanate in a propellant formulation has been studied. The kinetic rates for four different reaction temperatures have been measured both in gumstock and samples containing ammonium perchlorate. It is shown that the presence of ammonium perchlorate (up to 90% by weight) neither catalyzes nor retards the rate of binder polymerization. It is also shown that the polymerization follows an apparent second-order rate low with an activation energy of 9.8 kcal/mole.     

Synthesis, characterization, and controllable drug release of dendritic star-block copolymer by ring-opening polymerization and atom transfer radical polymerization

A series of well-defined dendritic star-block copolymers were successfully synthesized by combination of living ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP) with the hydroxyl-terminated dendrimer polyester. Dendritic star-shaped poly(l-lactide)s (PLLAs) were prepared by bulk polymerization of l-lactide (l-LA) with dendrimer polyester initiator and tin 2-ethylhexanoate catalyst. The number-average molecular weight of these polymers linearly increased with the molar ratio of l-LA to dendrimer initiator. Dendritic star-shaped PLLA was converted into a PLLABr macroinitiator with 2-bromopropionyl bromide. Dendritic star-block copolymers could be obtained via ATRP of 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA). The molecular weight distributions of these copolymers were narrow. The molecular weights of dendritic star-shaped polymers and star-block copolymers could be controlled by the molar ratios of monomer to initiator and monomer conversion. The thermal properties of these dendritic star-shaped polymers and star-block copolymers were investigated. The behavior of model drug chlorambucil release from the copolymer indicated that the rate of drug release could be effectively controlled by altering the pH values of the environment.     

Synthesis of star-shaped polymers by coupling reaction between multifunctional core and terminal functionalized polymers

Star-shaped polymers that consist of well-defined polystyrene (PS) arms were successfully synthesized in high yield by coupling reaction between multifunctional core molecules and hydroxyl-terminated PS in the presence of 1, 3-dicyclohexylcarbodiimide and 4-(dimethylamino) pyridine at room temperature. Several systems were investigated: (1) Pyromellitic dianhydride (PMDA) and hydroxyl-terminated PS (PS-OH) with narrow molecular weight distribution, which was prepared by atom transfer radical polymerization (ATRP) of St with 2-hydroxyethyl bromoisobutylate (HEBiB) as initiator. (2) PMDA and PS-OH prepared by conventional free radical polymerization, with 2-mercaptoethanol as chain transfer agent. (3) Narrow molecular weight distributed alternating copolymer of maleic anhydride (MA) and styrene (St), which was obtained via reversible addition fragmentation chain transfer polymerization (RAFT) process, and PS-OH obtained by ATRP. The formation of star-shaped PSs was confirmed by proton nuclear magnetic resonance (¹H NMR) and gel permeation chromatography (GPC).     

端羟基聚异戊二烯及其共聚物的合成与表征

以仲丁基锂为引发剂,引发异戊二烯本体负离子聚合,再用环氧丙烷甲醇终止法合成了端羟基聚异戊二烯;然后利用端羟基聚异戊二烯的活性端羟基,引发丙交酯的开环聚合制备了聚乳酸一聚异戊二烯共聚物,并采用IR、^1H—NMR、TG等测试手段对产品进行了表征。结果表明,通过改变仲丁基锂及环氧丙烷的用量,可合成相对分子质量及羟基含量可控的且1,4-结构质量分数超过87．5％的端羟基聚异戊二烯。     

Synthesis, characterization and thermal properties of hexaarmed star-shaped poly(ε-caprolactone)-b-poly(d,l-lactide-co-glycolide) initiated with hydroxyl-terminated cyclotriphosphazene

Hexakis[p-(hydroxymethyl)phenoxy]cyclotriphosphazene was prepared by the reaction of hexachlorocycltriphosphaneze with the sodium salt of 4-hydroxybenzaldehyde and subsequent reduction of aldehyde groups to alcohol groups by using sodium borohydride. Hexaarmed star-shaped hydroxyl-terminated poly(ε-caprolactone) (PCL) were successfully synthesized via ring-opening polymerization of ε-caprolactone (CL) with the above hydroxyl-terminated cyclotriphosphazene initiator and stannous octoate catalyst in bulk. The number-average molecular weight of PCL linearly increased with the molar ratio of monomer to initiator. The star-shaped PCL with hydroxy end groups could be used as a macroinitiator for block copolymerization with d,l-lactide (d,l-LA) and glycolide (GA) using stannous octoate catalyst. IR, ¹H NMR and GPC analysis showed the star-block copolymers were successfully synthesized and the molecular weights and the unit composition of the star-shaped block copolymers were controlled by the molar ratios of d,l-LA and GA monomers to CL. The copolymer presented a two-phase structure, namely, PCL crystalline and d,l-LAGA amorphous domains, which made the copolymer different from linear PCL and star-shaped PCL in crystallinity and thermal behaviors.     

以ZnEt2为调节剂的阴离子聚合合成聚丁二烯的研究（Ⅱ）

丁二烯在ｎ－ＢｕＬｉ或ｎ－ＢｕＬｉ／２Ｇ引发的阴离子聚合体系中，以环已烷为溶剂，在不同程度下，研究添加ＺｎＥｔ２调节剂对聚丁二烯结构的影响。结果表明：在ｎ－ＢｕＬｉ引发体系中，ＺｎＥｔ２的加入对聚合物的微观结构含量、分子量及分子量分布无影响。在ｎ－ＢｕＬｉ／２Ｇ引发体系中，ＺｕＥｔ２的加入导致聚合物的１，２－结构含量及分子量下降，但不影响聚合物的立构规整性和序列分布。