橡胶与弹性体增韧改性聚丙烯的研究进展

从橡胶、弹性体对聚丙烯(PP)进行增韧的机理出发,介绍了当前国内外研究较多的PP/橡胶与PP/弹性体二元共混物及其三元共混物。综述了采用具有不同结构的橡胶与弹性体、相容剂增容共混物以及无机材料协同弹性体对PP进行增韧改性的研究进展,同时也从共混加工工艺上对橡胶与弹性体增韧PP进行了阐述,分析了复合材料的综合性能,并对今后国内外增韧改性PP提出了展望。     

聚丙烯共混增韧研究进展

从塑料增韧聚丙烯（PP）体系，橡胶或热塑性弹性体增韧PP体系、PP／弹性体／塑料三元共混体系以及无机刚性粒子增韧PP体系4个方面详细论述了国内外PP共混增韧改性的研究进展。采用塑料类作为改性剂增专心PP，虽可增韧，但是由于体系的不相容性，往往要大量使用改性剂或添加相容剂。使用橡胶或者热塑性弹性体与PP共混增韧效果最为明显，但由于随着弹性体用量的增加，体系在冲击强度大幅度提高的同时也出现了刚性等性能的损失。PP弹性体／塑料三元共混体系可均衡改善力学性能及降低成本。此外，还就近年发展起来的无机刚性粒子增韧PP的研究工作进展和机理研究情况作了介绍。     

聚丙烯共混增韧改性研究进展

聚丙烯(PP)作为一种使用广泛的热塑性塑料,对其增韧改性一直是研究的重点,共混改性作为最常用的改性方法之一,受到科研工作者的关注。该文主要从与塑料共混增韧、与橡胶或弹性体共混增韧、与无机纳米粒子共混增韧、与有机/无机纳米材料共混增韧以及与其他材料(如:玻璃纤维、碳纤维、石墨烯、竹粉)共混增韧5个方面综述了近3年PP共混增韧改性的一些研究工作。     

UHMWPE/PP/PP基无机填料母粒复合材料的制备及表征

研究自制的PP基增强母粒对UHMWPE/PP共混体系的增韧、增强作用,并通过力学性能测试及扫描电子显微镜研究其增韧、增强效果.结果表明,PP基玻璃纤维(GF)母粒对UHMWPE/PP共混体系的增韧、增强作用优于添加增容剂聚丙烯接枝马来酸酐(PP-g-MAH)、GF的简单混合方法,这是因为前者试样中GF与UHMWPE/PP共混体系界面粘结的牢固程度大于后者.UHMWPE/PP共混体系中加入PP基纳米CaCO3母粒能够同时起到增强和增韧的作用.     

PP/EPDM共混体系增韧技术研究进展

从乙烯/丙烯/二烯烃共聚物(EPDM)增韧、β–PP晶增韧以及刚性粒子增韧等方面对PP/EPDM共混体系的增韧技术进行综述,展望了PP增韧改性研究的发展趋势。     

聚丙烯高性能化增韧改性探索

介绍了聚丙烯共混改性机理、共混体系结构形态对PP共混物性能的影响以及橡胶类聚合物对PP增韧改性原理和PP合金材料机理。     

聚丙烯高性能化增韧改性

介绍了聚丙烯共混改性机理，共混体系结构形态对PP共混物性能的影响以及橡胶类聚合物对PP增韧改性原理和PP合金材料机理。     

马来酸酐接枝乙烯-辛烯共聚物对聚对苯二甲酸丁二醇酯的增韧作用

研究了马来酸酐接枝乙烯-辛烯共聚物(POE—g—MAH)和POE—g—MAH／聚丙烯(PP)共混物对聚对苯二甲酸丁二醇酯(PBT)的增韧作用。结果表明,POE—g—MAH／PP共混物对PBT的增韧效果优于POE—g—MAH的,POE—g—MAH和PP并用具有显著的协同增韧作用。扫描电镜照片表明,POE—g-MAH／PP共混物增韧PBT具有软壳-硬核结构。     

PP/POE共混物性能分析

对聚丙烯(PP)和聚烯烃弹性体(POE)共混来增韧PP的效果进行研究，通过差示扫描量热计分析了共混物熔点、结晶温度及结晶焙的变化，利用广角X射线衍射仪、透射电镜分别分析了共混物PP晶面间距和共混物中POE的粒径大小和分布。得到PP和POE不同配比共混物性能变化规律。结果也表明，POE增韧PP与POE的添加量粒径大小及分布有密切关系。     

动态硫化增韧PP/EVAL共混物的研究

研究了简单共混和动态硫化增韧聚丙烯/皂化乙烯-醋酸乙烯酯共聚物(PP/EVAL)共混物的结构和性能。结果表明:以马来酸酐(MAH)为交联剂,用EVAL动态硫化增韧PP是一种可行的PP增韧方法;随着EVAL用量的增加,共混物的力学性能均随之变化,但动态硫化物的力学性能始终优于简单共混物;当EVAL质量分数为20%时,动态硫化物具有最佳综合性能,冲击强度达到26.5 kJ/m2,较纯PP增加了173.2%,为简单共混物的2.14倍;动态硫化可改善共混物中EVAL颗粒的分散效果;动态硫化可诱导PPβ晶型的形成并提高PP结晶度;动态硫化可增大共混物的内耗,从而增强材料韧性。     

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.     

新型白柠檬香精的合成

双戊烯与丙烯酸甲酯的加成物是一种无色透明、具有白柠檬香气的新型香精。用正交实验确定了合成加成物的最佳条件。通过质量和元素分析手段对产物进行了初步分析,测定了其沸点、折射率和密度等物理常数,并通过了评香鉴定。     

中空吹塑成型冷却过程分析

本文通过建立一维非稳态数学模型,对中空吹塑成型冷却过程进行了分析,并以ＬＤＰＥ为例,得以计算机辅助,获得冷却过程中的分析曲线,从而对中空吹塑成型的工艺设定和模具设计提出了相应的观点。     

METHOD FOR REGENERATION OF PLASTER OF PARIS*

A new method for the regeneration of gypsum from used molds has been evolved at the request of, and in collaboration with, the Gustavsberg Porcelain Works, Ltd. The reasons why regenerated plaster of Paris has previously been inferior to plaster made from rock gypsum have been elucidated. The method of regeneration, for which an application for a patent has been made (Swedish patent No. 119024, Regeneration of Plaster of Paris), has been tested on an industrial scale. These experiments show that molds made from “regenerated” plaster of Paris could be used just as long as good quality plaster was used. In certain cases they could be used even longer.     

EFFECT OF MAGNETIZATION OF WATER ON INDUCTION TIME AND GROWTH PERIOD OF NATURAL GAS HYDRATE

The effect of diluted solution's magnetization on induction time and growth period of natural gas hydrate (NGH) has been investigated in quiescent reaction system at pressure of 4.5 MPa and temperature of 274 K with SDS as surfactant, by using volume fixed and pressure falling method. Experimental results show that magnetization will have effect on the induction time of NGH. After magnetization with magnetic field intensity of 0.33 T, the induction time of NGH has been reduced to 47 min (average) from 99 min (average) in which there is no magnetization. On the other hand, the induction time has been prolonged after magnetization of the diluted solution with magnetic field intensity of 0.05 T, 0.11 T, 0.22 T, 0.44 T. Especially with magnetic field intensity of 0.11 T, the induction time had even been prolonged to 431 min (average). The effect of magnetization on the growth period of NGH has not been found at the experimental condition.     

煤中次要元素的赋存方式

对煤中次要元素的赋存方式进行了分析,讨论了元素赋存方式的研究方法,指出采用萃取方法和沉／浮方法结合将更有益于确定煤中次要元素的赋存方式,根据元素的矿物学类别详细讨论了煤中各次要元素的赋存方式。结果表明,次要元素在煤中的赋存方式远较其在矿物中的复杂。     

SIMULATION OF DEEP BED DRYING OF HAZELNUTS

Abstract

The deep bed drying modelling of hazelnut (Corylus avellana L.) have been studied by considering the deep bed as a series of thin layers. A partial differential equations model has been developed to simulate heat and mass transfer in fixed deep bed hazelnut dryers. The computer program developed permits the calculation of temperature and moisture content profiles along the dryer. As a process of validation of the model, the predicted and experimental results of average moisture content of the whole bed were compared. It has been observed that the simulation results agreed quite well with experimental data.     

电梯薄钣金件前处理施工工艺设计

介绍了电梯用薄钣金件前处理工艺中脱脂、表调、磷化工艺设计及参数等。     

KINETICS OF THE THERMAL DECOMPOSITION OF HYDRATED DOLOMITIC LIME AND SINTERING OF NASCENT CALCINE

A study is reported of the controlled thermal decomposition of hydrated dolomitic lime originated from a high-grade dolomite. Both increasing and constant temperature weight-loss methods have been employed to measure the rate of thermal dehydration of hydrated dolomitic lime at 305-400^°C. The amassed data have been correlated with the use of an Arrhenius-type rate equation. Changes in the specific surface area of calcines due to sintering phenomena have also been studied at 400-600^°C. An empirical, fractional-order kinetic relationship has been developed for surface area reduction as a function of temperature and elapsed time of sintering. Presented findings make it possible to specify the operation conditions needed for the preparation of reactive dolomite-derived sorbents.     

SIMULATION OF DEEP BED DRYING OF HAZELNUTS

The deep bed drying modelling of hazelnut (Corylus avellana L.) have been studied by considering the deep bed as a series of thin layers. A partial differential equations model has been developed to simulate heat and mass transfer in fixed deep bed hazelnut dryers. The computer program developed permits the calculation of temperature and moisture content profiles along the dryer. As a process of validation of the model, the predicted and experimental results of average moisture content of the whole bed were compared. It has been observed that the simulation results agreed quite well with experimental data.