PP／GF／纳米CaCO3复合材料的加工与性能研究

采用熔融共混方法制备了纳米碳酸钙/玻纤/聚丙烯(纳米CaCO3/GF/PP)复合材料,探讨了纳米复合材料的配方、生产工艺及纳米CaCO3对复合材料力学性能的影响.结果表明:纳米CaCO3对玻纤增强聚丙烯具有增强增韧作用;采用稀土复合偶联剂对纳米CaCO3进行表面活化处理,添加适量增容剂,对提高复合材料的力学性能具有较好的效果;添加3%的纳米CaCO3后复合材料的综合力学性能最好.     

P(St/MAH/BA)改性纳米CaCO3对PS的增韧研究

采用由苯乙烯(St)、马来酸酐(MAH)和丙烯酸丁酯(BA)组成的三元聚合物P(St/MAH/BA)作为纳米CaCO3-的表面改性剂,制备了纳米CaCO3/PS复合材料,并对复合材料的力学性能进行了测试.结果表明,P(St/MAH/BA)作为纳米CaCO3表面改性剂与PS的相容剂能够明显改善纳米CaCO3/PS复合材料的力学性能,经P(St/MAH/BA)改性的纳米CaCO3对PS具有明显的增韧改性作用.     

PP/EVA/纳米CaCO3复合体系力学性能的研究

采用双螺杆熔融共混法,以两种混合方式制备了聚丙烯(PP)/乙烯醋酸乙烯酯(EVA)/纳米碳酸钙(CaCO3)复合材料.研究了纳米CaCO3用量对复合材料力学性能的影响.研究结果表明:经表面处理的纳米CaCO3粒子的加入对复合材料有明显的增韧效果.两种不同混合方式最佳纳米CaCO3用量均为3%左右.采取先将PP与EVA共混挤出后再与纳米CaCO3进行混合挤出的两步法工艺,制得的复合材料的综合性能较优.     

正交设计在改性纳米CaCO3/PVC复合体系中的应用

选择不同的方法对纳米CaCO3进行表面改性,研究了表面处理剂对CaCO3/PVC纳米复合材料界面结合强度、力学性能及加工性能的影响。通过正交实验设计得到了力学性能最佳时的制备条件:表面处理剂选用钛酸酯偶联剂,其用量4%(质量分数),纳米CaCO3用量15%(质量分数)。极差分析结果表明,对冲击强度而言,主要影响因素为表面处理剂用量;扫描电镜显示,钛酸酯偶联剂处理可使纳米CaCO3颗粒在PVC基体中达到良好分散,并提高其界面结合强度;流变性能研究表明,经钛酸酯处理的纳米CaCO3填充PVC具有更低的平衡转矩。     

聚丙烯/轻质CaCO_3复合材料的力学性能研究

采用熔融共混的方法制备了PP/CaCO3复合材料,并研究了轻质CaCO3的表面处理、含量及粒径对材料的拉伸强度和缺口冲击强度两大主要力学性能的影响,着重对实验结果作了科学的理论分析。实验结果表明,钛酸酯类偶联剂能很好地改善CaCO3粒子与PP基体的界面相容性,从而使复合材料的力学性能提高;经表面处理后的超细轻质CaCO3(纳米级)所填充复合材料的拉伸强度和缺口冲击强度明显优于普通轻质CaCO3(微米级);而且处理后的纳米级CaCO3在填充量为10%时对PP的增强增韧效果最佳。     

PVC／纳米CaCO3复合材料的研究

研究了表面经硅烷处理的纳米CaCO3填充PVC复合材料的力学性能。结果表明：用量为0.2％的KH-570表面处理过的15份纳米CaCO3对PVC有显著的补强与产韧效果。初步推论了PVC／纳米CaCO3的复合增韧机理.     

纳米CaCO_3/EVA/PP共混制备多孔聚丙烯纤维

以纳米CaCO3为成孔剂,与聚丙烯(PP)、乙烯-乙酸乙烯酯嵌段共聚物(EVA)相混合制得共混纤维,将共混纤维进行酸处理和醇解处理后得到多孔聚丙烯纤维。研究了纳米CaCO3/EVA/PP共混物的力学性能,考察了纳米CaCO3/EVA/PP共混纤维的回潮率与表面形态。结果表明:随着EVA含量的增加,纳米CaCO3/EVA/PP共混纤维的力学性能下降,回潮率上升,纤维表面的微孔更加密集、均匀。     

纳米CaCO3/PP复合材料的制备与性能研究

分别采用钛酸酯偶联剂、硅烷偶联剂、铝酸酯偶联剂等对纳米CaCO3进行表面处理,通过熔融共混法制备了纳米CaCO3/PP复合材料,并进行了力学性能测试与表征.结果表明,经过三种偶联剂处理后的纳米CaCO3能显著提高PP的缺口冲击韧性,其中NDZ-201钛酸酯偶联剂的处理效果最佳,当纳米CaCO3质量分数为7%时,对PP的改性效果最好,缺口冲击韧性提高了38%,弯曲模量提高了33%.     

力化学处理纳米CaCO3/ACR复合粒子对PVC力学性能的影响

通过力化学方法制备了纳米CaCO3／ACR母粒,并研究了其对PVC力学性能的影响;通过SEM方法观察了拉伸试样纵断面裂纹的发展情况和冲击脆断面粒子的分布情况。研究结果表明：纳米CaCO3经过丙烯酸丁酯表面处理后再与ACR共振磨处理能有效地改善纳米CaCO3与聚合物之间的界面粘接,使其界面粘接增强,有利于提高复合体系的力学性能。     

PP／湿法表面处理纳米CaCO3复合材料的力学性能研究

研究了自制水溶性钛酸酯偶联剂对新型超重力反应结晶法所得纳米碳酸钙浆料进行湿法表面处理的配方和工艺。系统研究了纳米CaCO3用量和表面处理剂种类对：PPA纳米CaCO3复合材料形态结构和力学性能的影响。结果表明，采用偶联剂处理的纳米CaCO3在基体中的分散优于脂肪酸盐。纳米CaCO3经表面处理，在低含量时(5～6份)即可对PP进行有效地增韧改性，偶联剂和脂肪酸盐处理的两种纳米CaCO3分别使PP冲击强度提高70％和50％，且拉仲强度保持不变。DSC和WAXD研究复合材料中PP的晶体结构发现，PP β-晶型的成核结晶与表面处理剂种类密切相关。     

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。     

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。     

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…     

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。