【作者】 戴信飞；

【导师】 刘兆峰；

【作者基本信息】 东华大学 ， 材料学， 2005， 硕士

【摘要】 聚对苯二甲酰对苯二胺Poly （para-phenylene terephthanlamide,简称PPTA）纤维,是一种高科技纤维,具有高强高模、耐高温等一系列优良性能,然而,PPTA树脂难溶难熔,必须在浓硫酸中进行纺丝,加工比较困难。本论文重点是以4,4’-二氨基二苯醚（ODA）为第三单体与对苯二甲酰氯（TPC）、对苯二胺（PPD）进行了三元共缩聚改性,研究PPTA的低温溶液共缩聚合成规律,制备出一系列高相对分子质量的溶于N-甲基吡咯烷酮/氯化钙（NMP/CaCl₂）的芳香族聚酰胺。通过分析其热性能、结晶性能、溶解性能、共聚物纺丝溶液的凝固性能、流变性能,稳定性能,最终得到热稳定性较好,适于原液纺丝的共聚物溶液。 对PPTA低温溶液共缩聚反应规律、加料方式进行了研究,确定了ODA含量25mol%混合投料的共聚PPTA的最佳工艺条件:氯化钙/二胺摩尔比约为0.375,单体浓度为0.35～0.45mol/L,爬杆后温度为80～85℃,总反应时间为30～40min,合成出来的聚合物比浓对数粘度最高。另外还制备了两个系列的共聚物,系列一为混合投料时只改变三单含量而得到的共聚物系列,系列二是ODA含量为25mol%,投料方式为分步投料,只改变其初始投料比而得到的共聚物系列,两个系列都具有较高的比浓对数粘度（2.05～3.37 dL/g）。通过FTIR表征,可发现样品中苯撑的含量随参与反应的ODA含量的增加而上升,说明ODA参与了共聚反应。 热失重和热分解动力学研究表明,共聚改性后的PPTA开始分解温度、分解活化能和分解指数低于未改性的PPTA,但热稳定性依然良好5% N₂气氛热失重温度361～401℃。 溶解性能的测试表明所合成的绝大多数PPTA共聚物溶于NMP/CaCl₂体系,然而研究发现,在不同ODA含量的共聚物系列（混合投料）,当ODA含量小于15mol%,合成出来的聚合物不溶于NMP/CaCl₂体系。在不同初始投料比系列里（）初始投料比(ODA/TPCl（mol/mol）小于1.9时,合成出来的聚合物不溶于NMP/CaCl₂体系。这与PPTA的广角X衍射结果相一致,ODA含量小于15mol%（混合投料）时均聚PPTA和共聚PPTA的结晶度非常接近在40%左右;当ODA含量大于或等于15mol%（混合投料）时,结晶度从均聚的40%突降到20%左右,说明15mol%ODA的引入破坏了高分子链的规整性,使其晶体难以形成,而无定型区的更多还原

【Abstract】 Poly （Para-Phenylene Terephthalamide） is a high performance polymer, but difficult to process because of its poor solubility. Copolycondensation by adding 4, 4’-Diaminodiphenyl ether （ODA） into the polymerization system is one of effective methods to improve the solubility of PPTA. In this paper, the copolyamides were prepared by low temperature solution copolycondensation using p-phenylenediamine, terephthaloyl chloride and ODA in the solvent system of N-methyl-2-pyrrolidone /calcium （NMP/CaCl2）. The chemical structures of copolyamides were calculated semi quantitatively by FTIR. The optimum synthesis conditions were investigated, and high molecular weight copolyamides were obtained. The thermal behavior, thermal degradation kinetics, the rheological properties, the crystalline degree of the series copolyamides were studied by using thermo gravimetric analysis （TGA）, rheology instrument and Wide angle X-ray diffraction. The solubility and coagulation phase separation of the copolymer solution of the copolyamides were also discussed.The conditions such as the reaction time, the reaction temperature, the amount of CaCl₂, the monomer concentration, the initial ratio of ODA /TPCl on the molecular weight of PPTA copolyamides were studied. Two series of high weight copolyamides （inherent viscosity 2.05-3.37dL/g） were prepared, including a different ODA content series which were synthesized by random copolymerization ,and a different initial ratio of ODA /TPCl series（25mol%ODA） which were synthesized by control the feed order. The optimal conditions were: monomer concentration of 0.35⁰.45mol/L, the final reaction temperature 80-85 ℃, the ratio of CaCl₂/diamine 0.375, and polymerization time 30-40 minutes. It was indicated that the content of - O-in the copolymers increased with the increase of the ODA content by FTIR.The TGA curves of the copolyamides indicated the copolymers had good thermal stability. 5% weight loss were in the ranges of 361-401 ℃.Most of the synthesized copolyamides were soluble in NMP/CaCl2 system, butwhen the ODA content was less than 15mol% in the different ODA content series, and the initial ratio of ODA/TPC1 was less than 1.9 in different initial ratio of ODA/TPC1 series（25mol%ODA）, the copolyamides were insoluble. The solubility behavior is consistent with the result of x-ray diffraction studies. The X-ray diffraction pattens indicated when the ODA content less than 15mol% the crystallinity was about 40%, when the ODA content more than 15mol% the crystalline was rapidly decreased.Non-Newton exponent, viscous activation energy, structural viscosity index were obtained by studies of rheology properties of the dopes for the subsequent spinning process.The dependences of coagulation value and critical concentration of the solvent （NMP） on coagulant, coagulant concentration, temperature, concentration of CaCl₂ were investigated. It is shown that water was a kind of strong coagulant for its low coagulation value and that the coagulation value increased with the increase of coagulation concentration, CaCl₂ concentration and temperature.The shift life studies show most of the copolyamides spinning dopes was stable at room temperature and spinning temperature （70℃）, whereas the PPTA concentrated sulfic acid spinning dope degraded quickly after 24 hour.更多还原