引进1,2-丙二醇共聚单体制备新型共聚酯的研究

采用直接酯化工艺路线,以对苯二甲酸、乙二醇、1,2-丙二醇为原料合成了一种新型共聚酯——聚对苯二甲酸丙二醇酯-co-对苯二甲酸乙二醇酯(PPET)。研究了该共聚酯的聚合工艺条件,并对制备的共聚酯进行了性能测试。结果表明:共聚酯聚合工艺受总醇与酸的摩尔比、催化剂种类和用量、稳定剂用量、聚合温度等条件的影响;新型共聚酯注塑性能较好,并具有一些特殊性能。     

PET-PCT共聚酯的制备及其热性能研究

由直接酯化法制备了不同1,4-环己烷二甲醇(CHDM)含量的聚对苯二甲酸乙二醇酯-聚对苯二甲酸-1,4-环己烷二甲醇酯(PET-PCT)共聚酯;利用核磁共振表征了合成产物的实际组成及序列结构;采用差示扫描量热和热失重分析研究了共聚酯的结晶特性和热稳定性。结果表明:合成的共聚酯为无规嵌段聚合物,PCT的实际组成均高于投料比,各链段的序列长度与其含量成正比。随着CHDM含量的增加,共聚酯的玻璃化转变温度升高,退火后的试样在低温处和高温处出现了两个熔点,且熔点和焓值随PCT含量的增加而降低。合成产物热稳定性优良,起始分解温度均大于400℃,最大分解温度大于435℃。用Friedman法对热分解动力学的分析,进一步证明共聚酯的热稳定性优良。     

Thermal decomposition kinetics of thermotropic poly(oxybenzoate‐co‐trimethylene terephthalate)

A new kind of thermotropic liquid crystalline, poly(oxybenzoate‐co‐trimethylene terephthalate), was prepared from p‐hydroxybenzoic acid (B) and poly(trimethylene terephthalate) (PTT or T) by melting polycondensation. The monomer ratio of B to T is 60:40. The dynamic thermogravimetric kinetics of the copolymer B/T (60:40) and PTT in nitrogen were analyzed by four single heating rate techniques and two multiple heating rate techniques. The effects of the heating rate and the calculating technique on the thermostable and degradation kinetic parameters of the B/T copolymer and PTT are systematically discussed. The four single heating rate techniques used in this work include Friedman, Freeman‐Carroll, Chang, and the second Kissinger techniques, whereas the two multiple heating rate techniques are the first Kissinger and Flynn‐Wall techniques. Additionally, the isothermal thermogravimetric kinetics of B/T (60:40) in nitrogen were investigated by the Flynn technique. The activation energy, the order, and the frequency factor of the degradation reaction for B/T (60:40) copolymer are determined to be 185 kJ/mol, 1.8, and 7.14 × 10¹³ min⁻¹, respectively. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2025–2036, 2000     

Thermal properties and chemical changes in blend melt spinning of cellulose acetate butyrate and a novel cationic dyeable copolyester

A novel cationic dyeable copolyester (MCDP) containing purified terephthalate acid (PTA), ethylene glycol (EG), 2‐methyl‐1,3‐propanediol (MPD), and sodium‐5‐sulfo‐isophthalate (SIP) was synthesized via direct esterification method. The chemical structure of modified cationic dyeable polyester (MCPD) was confirmed by FTIR and ¹H‐NMR. The thermal properties of MCDP and cellulose acetate butyrate (CAB) blends with different blend ratios were investigated by DSC. The results revealed that MCDP and CAB were immiscible polymer blends, and the glass transition temperature of CAB in blend fibers was higher than that of CAB in blend chips because of the strengthening hydrogen bonding. The chemical changes of MCDP and CAB in blend melt spinning were analyzed. It was found that the thermal hydrolysis reaction of ester side groups of CAB occurred in blend melt spinning, which resulted in that the acid gas was produced and the hydroxyl group content of CAB was increased. Furthermore, the moisture absorption of blend fibers was improved about three times than pure MCDP fiber even after washing 30 times. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

不同催化剂合成的聚酯、共聚酯结晶行为的研究

运用ＤＴＡ、结晶速度仪对不同催化体系合成的ＰＥＴ、ＰＥＴＡ、ＰＥＴＩ的结晶行为进行了研究。观察了Ｔｃｃ、ｔ(１／２)和ｔｉ的变化，并计算出结晶动力学常数■和Ａｖｒａｍｉ指数ｎ，就此分析了三者在成核阶段、晶粒生长阶段及整体上的结晶速度的差异，以及造成这些差异的原因。