热处理过程中聚酯长丝的形态变化

在自制的红外三因素处理机上~[1],用红外加热在定张力下对聚对苯二甲酸乙二酯(PET)成品长丝进行热处理(二次定型)。用X-光衍射(WAXS)、X-光小角散射(DAXS)、红外光谱(IR)和双折射方法,测定样品的热收缩、结晶度、晶粒尺寸和取向、非晶取向、长周期和链折叠带强度。所得形态参数的变化表明,处理温度在200℃以上时,张力不再阻碍链折叠。不同定张力样品的形态研究表明,存在阻碍链折叠的某个张力转折值。本文条件下,这个张力值为f_(critical)=0.066g/dtex 。张力大于此值,链折叠过程受阻。     

对苯二甲酸乙二酯-癸二酸乙二酯共聚物纤维的超分子结构研究

用宽角和小角X射线散射技术测定了聚对苯二甲酸乙二酯(PET)纤维及其与不同含量的癸二酸乙二酯(ES)的无规共聚酯纤维的结晶度、晶区取向度、晶粒尺寸和长周期等超分子结构参数。考查了它们的DSC和动态力学行为。结果表明,一维两相结构模型不适应于本文的聚酯纤维结构体系。Prevorsek的三相模型加以适当改进后,可以较满意地解释实验现象。     

方差方法用于高聚物X光衍射峰形的分析

假设PET纤维中的晶格畸变可用次晶模型描述, 用其x光衍射105的方差-区间函数测定出一组热处理样品的晶粒尺寸和晶格畸变因子。说明了此法所得晶粒尺寸为“数均”尺寸。发现样品中晶区的完善性随其热处理温度的升高而改善; 晶粒尺寸与畸变因子之间的关系符合Hosemann的a~*定则。     

PBT-PA6嵌段共聚物中嵌段间的相容性

用热分析、动态粘弹谱、红外光谱和小角X光散射的实验结果,证实了在聚对苯二甲酸丁二酯-聚己内酰胺嵌段共聚物(简称PBT-PA_6)的无定形区中,两嵌段间具有良好的相容性,两嵌段间有氢键生成。     

CRYSTALLIZATION AND MULTI-MELTING BEHAVIOR OF POLY (ETHYLENE TEREPHTHALATE) MODIFIED BY SODIUM SALT OF 5-SULPHO-ISOPHTHALIC ACID

The crystallization kinetics of the copolyester, poly(ethylene terephthalate) (PET) modified by sodium salt of 5-sulpho-isophthalic acid(SIPM), was investigated by means of differential scanning calorimeter. The experimental results and polari-microscopy observation all showed that the introduction of SIPM did not affect the nucleation of crystallization. Within the temperature range between their glass transition temperature T_θand melting point T_m, the crystallization rate of the copolyester sample decreased with increasing content of SIPM. The relative crystallization rate constant Z of SIPM/DMT (dimethyl terephthalate) 4mol % sample was about 1% pure PET's Z value. For isothermal crystallized copolyester samples, DSC heating curves displayed multi-melting behavior. This was interpreted by molecular weight fractionation during crystallization and premelting-recrystallization mechanism. This interpretation showed why the second melting point T_(m2) will change according to Hoffman-Weeks(H-W) equation and the first melting point T_(m1) will increase with increasing SIPM. The principal cause of these phenomena is the high temperature crystallization rate decreases rapidly with increasing SIPM.     

PET纤维中的次晶结构及晶粒增大的机理

用方差-范围函数的方法分析了一组热处理PET纤维的X光衍射数据,测出了各样品(010)和(100)方向上的晶粒尺寸M、第二类晶格畸变的畸变因子g及晶粒尺寸分散性指数.发现在T~*=503K处,曲线InM～1/T.上出现折点,晶粒尺寸分散性指数出现极大值.据此提出样品中晶粒增大的机理:当T相似文献   

冷拉伸无定形聚酯纤维的形态研究

本文用差示扫描量热法与X光衍射法相结合,研究涤纶无定形纤维在室温下拉伸后,超分子结构形态的变化。由于采用非晶样品,在一定条件下避免了晶区的出现,肯定了在T_g附近的DSC的宽放热峰包是取向结晶的贡献。它可能是“第三相”的部分热行为。