PBT/PET共混切片结晶性质的研究

本研究采用JJY-Ⅰ型光学检偏振仪测试不同配比PBT/PET共混切片的等温结晶性质,用电子计算机处理数据,获得了PBT/PET共混切片的等温结晶动力学参数。并采用准等温处理方法,将等温结晶动力学参数用于非等温过程中,得到不同配比PBT/PET共混切片一系列结晶动力学特性参数。从其中的动力学结晶能力G,可判断在同一稳态纺丝条件下,不同配比PBT/PET卷绕丝的相对结晶度大小;采用PEDSC-Ⅱ型测试了不同共混配比的PBT/PET切片的非等温结晶性质,其结果和用JJY-Ⅰ型测试结果一致;本研究还探讨了添加剂(成核剂)对PBT/PET共混切片结晶性质的影响。     

凹凸棒土/尼龙66复合材料的非等温结晶动力学研究

<正>尼龙66为一种结晶型聚合物,在实际生产过程中,如熔融纺丝、挤出、模压、吹塑等,常常是在动态、非等温条件下完成的,所以其结晶过程为一非等温结晶过程。为了选择合适的加工工艺条件,定量地研究非等温结晶动力学日益受到重视。非等温结晶过程要综合考虑温度(T)与结晶时间(t)的关系,其     

低温橡胶粉碎技术发展综述

一、橡胶的物理形态 橡胶大分子链时刻都处于运动状态，因此大分子链以直线状态存在的可能性是很小的。绝大多数情况下是处于卷曲状态。研究表明，橡胶有两种聚集状态，即结晶态和非结晶态（也叫无定形态）。橡胶的结晶态多发生在低温或处于拉伸的状态。在通常情况下，橡胶都处于非结晶态。     

染色剂对锦纶-6结构性质影响

用差示扫描量热法(DSC)和X-射线衍射法研究了染色剂对锦纶-6(PA-6)热性能和品态结构的影响。其结果表明,可溶性染料影响染色PA-6的熔点,促进PA-6品态结构中γ晶态的成长。染色PA-6拉伸丝,总结晶指数不变,(γ+h)晶态中h部分转变为α晶态。松弛热处理能使染色PA-6丝中无定型结构直接转变为α晶态结构,h晶态全部转化为α晶态,因此热处理的PA-6丝α晶态和总结晶指数明显增加。     

科技成果转让

[20-51] 聚烯烃塑料用增韧母粒 利用经过特殊表面处理的超细碳酸钙加入聚烯烃塑料(HDPE、PP)后所产生的界面结晶效应,改变聚烯烃树脂在成型冷却过程中所形成的晶态结构、织态结构,控制制得材料内部晶态和织态结构都处于优化状态的聚烯烃塑料复合材料,可使该复合材料的缺口冲击韧性     

PA11/SiC复合材料非等温结晶动力学研究

通过熔融共混法制备了尼龙11/碳化硅(PA11/SiC)复合材料,利用差示扫描量热仪(DSC)研究了该复合材料的非等温结晶过程,且采用Avrami方程修正的Jeziorny法和Mo法对其非等温结晶动力学进行了研究,并计算得到相关非等温结晶动力学参数。结果表明:Jeziorny法和Mo法都适用于处理PA11及PA11/SiC复合材料的非等温结晶过程,其分析结果均显示,SiC的加入影响了PA11复合材料的非等温结晶行为,少量(1%)SiC的加入促进了PA11复合材料的成核及晶体生长,提高了结晶速率;由Jeziorny法可知,PA11及其复合材料的非等温过程可分为初期结晶和二次结晶两个阶段,在二次结晶阶段,结晶方式为一维线性、二维盘状和三维球晶生长并存。     

不同温度和冷却速率下高温灰渣的结晶行为

采用单热电偶在线观察系统(SHTT)、图像分析程序等研究等温过程中温度和连续冷却过程中冷却速率对于人工配制灰渣结晶行为的影响,通过计算结晶动力学参数分析其析晶机理,并采用Fact Sage软件预测晶体类型。实验结果表明,等温过程中,温度降低,结晶所需时间先减小后增大,晶体尺寸减小,结晶比例先增大再稳定最后减小,不同温度区间生成晶体类型不同,导致结晶比例在某些温度出现较大的变化。连续冷却过程中,冷却速率增大,初始结晶温度降低,晶体由块状向颗粒状转变,结晶比例先稳定后减小,由于析出的晶体类型不同,结晶比例出现多个稳定区间,达到临界冷却速率后熔渣全部凝固为玻璃态,无晶体析出。由DSC得到的熔渣结晶放热曲线与SHTT得到的结果吻合较好。     

不同温度和冷却速率下高温灰渣的结晶行为

采用单热电偶在线观察系统（SHTT）、图像分析程序等研究等温过程中温度和连续冷却过程中冷却速率对于人工配制灰渣结晶行为的影响,通过计算结晶动力学参数分析其析晶机理,并采用FactSage软件预测晶体类型。实验结果表明,等温过程中,温度降低,结晶所需时间先减小后增大,晶体尺寸减小,结晶比例先增大再稳定最后减小,不同温度区间生成晶体类型不同,导致结晶比例在某些温度出现较大的变化。连续冷却过程中,冷却速率增大,初始结晶温度降低,晶体由块状向颗粒状转变,结晶比例先稳定后减小,由于析出的晶体类型不同,结晶比例出现多个稳定区间,达到临界冷却速率后熔渣全部凝固为玻璃态,无晶体析出。由DSC得到的熔渣结晶放热曲线与SHTT得到的结果吻合较好。     

硅灰石填充尼龙-6复合体系的非等温结晶行为及动力学研究

用差示扫描量热法(DSC)考察了硅灰石填充尼龙-6复合体系的非等温结晶行为,并用Avrami以及Mo法研究了其非等温结晶动力学。结果表明,随着降温速率的增加,复合体系的结晶峰变宽并向低温方向移动,结晶速率增加。通过对比,Mo法能很好地描述硅灰石填充尼龙-6复合体系的非等温过程。     

高聚物结晶形态精细结构的电镜研究

前言高分子材料性能与其聚集态密切相关,而聚集态又有晶态和非晶态之分。考虑到结晶度、结晶形态及结晶在材料中的织态结构对于结晶高聚物的物理性质与化学性质的影响,人们对各类高聚物(特别是作为主要高分子材料之一的聚丙烯)进行了以球晶结构     

氢气纯度分析方法准确性的探讨

ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l／3为氧气,2／3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中：A一混…     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

几种针状焦性能对比

针状焦分石油系和煤系两大类,这主要取决于针状焦的原料来源。在同一系列中由于原料不同和工艺条件不同 ,针状焦的各自性能也不相同。针状焦是生产超高功率石墨电极和高功率石墨电极的主要原料 ,针状焦的性能对石墨电极的质量有至关重要的影响。所以对针状焦性能以及其对石墨电极质量影响的研究十分必要的。以下是常用的几种进口针状焦和国产针状焦的性能对比。１原料性能分析对比原料试样包括４种针状焦 ,其中两种为进口针状焦：三菱针状焦和新日化针状焦;另两种为国产针状焦：鞍山针状焦和锦州针状焦。其中除锦州针状焦是石油系针状焦外…     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

聚酰亚胺的合成法

本文评述了缩聚型聚酰亚胺的主要合成方法和近年来国际上在合成中所做的探索。