根据两相声速模量理论测定纤维非晶区取向因素f_(am)的变化

一般的高聚物材料是一种包含有晶相和非晶相的两相体系。众所周知,用X线衍射法可以测定纤维的晶区取向因素f_c,但对于非晶区取向因素f_(am)却还缺乏一种直接和精确的测量方法。在 Moseley 声速取向理论的基础上,Samuels 进一步提出了两相声速模量理论,并推导出以下公式:此处,E_(or)——部分取向试样的实测声速模量;E_(t·c)~0,E_(t·am)~0——分别为试样的晶区和非晶区的特征横向杨氏模量;f_c,f_(am)——试样的晶区和非晶区取向因素;β——试样结晶度。从上式中可以看到,对一定的试样而言,E_(t·c)~0和E_(t·am)~0均为常数,因此只要测出试样的声速模量E_(or)、结晶度β和晶区取向因素f_c,则就可以计算非晶区取向因素f_(am)。我们用高速PET纤维(6000米/分)作为试样,在不同条件下进行紧张热定型处理,然后分别测定E_(or)、β和f_c,并进一步计算f_(am)。从实验结果可以得到三点结论:1.随着热定型温度的提高,试样的结晶度提高,但同时非晶区取向因素f_(am)随之下降.2.f_(am)随着热处理中对试样施加张力的增加而增加,且两者呈线性关系;3.f_(am)随张力而变化的曲线的斜率,在不同的温度下有所不同,温度增高,曲线的斜率也增大。     

THE INFLUENCE OF DRAWING CONDITIONS OF PET POY ON STRUCTURE AND PROPERTY OF THE FIBER

Drawing tests upon PET POY have been made by using dynamic thermal stress analyser,which show that the dynamic thermal stress of fiber is readily affected by drawing conditions. Aseries of samples have been obtained under different drawing velocities, drawing temperatures anddraw ratios. The variations of structural factors of fiber such as the orientation, crystallinity,crystallite size and the thermal shrinkage have been measured. It is proved through experimentsthat the thermal shrinkage(Y) of the drawn fiber of PET POY is influenced by the orientation (rep-resented by sonic velocity x_1) and crystallinity (x_2) of the fiber. The quantitative relationship is es-tablished using the binary regression method: Y=10.2246+2.2030x_1-26.2670x_2 The mechanical properties such as tenacity, elongation, yield stress, initial modulus and the te-nacity at 10% elongation, etc. have also been measured. The relations between the tenacity at 10%elongation (D) and drawing velocity(V), draw ratio (DR), drawing temperature (T), and sonic ve-locity and crystallinity have been obtained using a method of mathematical statistics: D=4.594-0.009 6V , D=-8.937+7.170DR, D=2.866+0.00629T, D=-7.34+2.866x_1+6.314x_2 These equations fit well with data from the experiments. This work will be benefical to the control of quality of products and the development of newproducts.     

涤纶多孔纺丝过程中温度、速度、张力径向分布问题的研究

本文建立了在密闭环吹条件下,多孔纺丝过程的数学模型.借计算机求得各层纤维温度、速度、张力、速度梯度沿纺程的分布和各层纤维凝固距离、双折射△n等变化.对探讨纺丝机理、选择最佳工艺、改进设备提供有益参考.     

涤纶POY的热收缩和动态内应力

本文利用动态内应力仪对各种纺速和纤度的涤纶POY进行拉伸试验。研究不同纺速、纤度及拉伸条件下POY的动态内应力变化规律,并对制取样品的结晶度、声速、双折射、热收缩率和色差等进行测定。试验表明:(1)纺速为3000～3300m/min的POY动态内应力最低;(2)纤维的色差值随动态内应力波动值增大而增加;(3)纤维的热收缩率取决于超分子结构参数——结晶度与取向度。它随大分子取向度的增加而增大,随结晶度的增大而下降。用二元回归的数理统计方法得到热收缩率和纤维的结晶度以及表征大分子取向的声速、双折射间的定量关系:Y=67.5999+0.3225X_1-3.2430X_2 R=0.9985(纺速1100m/min～5500m/min)式中:Y——纤维的热收缩率;X_1——纤维的双折射;X_2——纤维的结晶度;R——全相关系数。Y=21.4447+1.8558X_1-10.3050X_2 R=0.9993(纤度45dtex/24f～167dtex/30f)Y=10.2246+2.2030X_1-26.2679X_2 R=0.9916(拉伸倍数1.4～2.2)X_1——纤维的声速值。     

AN INNOVATED REACTOR WITH VARYING DIAMETER AGITATOR AND ITS APPLICATIONS

The reactor is equipped with two different types of agitators: the diameter-variable agitator and the two-pitched-paddle agitator. The diameter of the former can be varied according to the requirement of the chemical reactions, thus making the concentration and temperature of the whole reaction system uniform throughout the reactor without any stagnant zone. It is shown that the apparatus has the preponderance over conventional agitator, especially when extremely rapid reactions are accompanied by large amount of reaction heat and when the viscosity of the reaction system varies in a wide range. The reactor is very effective when applied to the polycondensation reaction between paraphenylene diamine (PPDA) and terephthyl chloride (TPC). The inherent viscosity (η_(inh)) of the polymer comes up to more than 5. This innovative agitator has the advantage of simplicity in structure and flexibility in operation, etc.