The effect of nucleating agents on glycerol monostearate antistat performance in three polypropylene resins

The effect of polypropylene nucleation on glycerol ester antistat performance is studied by measuring the electrostatic decay times of injection molded specimens. Behaviors in homopolymer, random copolymer, and block copolymer are compared. Antistat performance is related to crystallinity using DSC.     

Study on poly(vinyl chloride) paste blending resins

Polyvinyl chloride paste blending resins were prepared by a suspension polymerization process, and the optimum ingredients and technological conditions were studied experimentally. The effect of dispersant, surfactant, and agitator design on the particle morphology was discussed. In order to improve the thermal stability of the blending resin, stabilizer was added to the polymerization system, and a special after-treatment was adopted. The effect of blending resins on the rheological and gelation characteristics of the plastisols formed and on mechanical properties, thermal stability, and foamability of the finished articles is demonstrated.     

Reactive blending of functionalized acrylic rubbers and epoxy resins

A high molecular weight acrylonitrile/butadiene/methacrylic acid (Nipol 1472) rubber is chosen to control processability and mechanical properties of a TGDDM (tetra glycidyl diphenyl methane) based epoxy resin formulation for aerospace composite applications. The physical blend of rubber and epoxy resin, achieved by dissolution of all the components in a common solvent, forms a heterogeneous system after solvent removal and presents coarse phase separation during cure that impairs any practical relevance of this material. A marked improvement of rubberepoxy miscibility is achieved by reactive blending (‘pre‐reaction’) the epoxy oligomer with the functional groups present in the rubber. The epoxy‐rubber ‘adduct’ so obtained appears as a homogeneous system at room temperature and also after compounding with the curing agent. Depending on the nature and extent of interactions developed between the rubber and the epoxy resin during ‘pre‐reaction,’ materials with different resin flow characteristics, distinctive morphologies and mechanical properties after curing were obtained. The effect of ‘pre‐reaction’ on the resin cure reaction kinetics has been also investigated.     

The effect of molecular weight blending on PVC melt rheology

The effect of molecular weight blending on melt flow characteristics has been studied with a 50/50 mixture of suspension PVC resins with the respective M _w of 56,300 and 123,000. The dynamic shear measurements were made with the Rheometrics Visco-Elastic Tester at angular frequencies of 0.1 to 40 radians/s. In the temperature range of 160 to 215° C, all samples showed three distinct flow regions marked by three different values of the activation energy. The high molecular weight fraction introduced a relatively strong influence on the melt flow characteristics of the blend due to the effect of its relatively high crystalline content. These samples also failed to show a Newtonian flow behavior at 190°C at an extremely low shear rate corresponding to 10^?4 radians/s., possibly reflecting the effect of the remnant crystallinity of the material.     

月桂酰丙氨酸钠的复配性能研究

用月桂酰丙氨酸钠(SLA)分别与脂肪醇聚氧乙烯醚硫酸钠(AES)、椰油酰胺丙基甜菜碱(CAB)和烷基糖苷1214(APG)进行复配,测定了复配体系的表面活性、泡沫性能、润湿性能和钙皂分散性能。结果表明:单一SLA的表面活性优于其他3种表面活性剂,复配体系的表面活性总体随SLA加入量的增加呈上升趋势;SLA的泡沫性能和钙皂分散性能较差,但是通过复配,SLA的两个性能均得到改善;当SLA与AES、CAB和APG三者的质量比均在5∶1时,复配体系的润湿力达到最大,均产生协同作用。     

The condensate polishing performance of powdered ion-exchange resins

The coating properties and ion-exchange performance of powdered ion-exchange resins were examined in a small test facility. Satisfactory resin coatings were obtained with cation : anion resin ratios in the range 1 : 1 to 3 : 1, but a 9 : 1 resin ratio resulted in a high pressure drop across the coating. The “settled resin volume” proved to be a reliable guide to the coating performance of resin slurries. The ion-exchange capacity of the cation resin increased from 2.5 to 2.8 equiv./kg as the sodium concentration in the influent decreased from 49 to 0.5 mg 1^?1. Within the ranges examined, resin ratio, resin loading and flowrate had no significant effect on cation capacity. The ion-exchange capacity of the anion resin for chloride ions was 2.2 to 2.3 equiv/kg at ambient temperature but exposure of the resin for four days at 80 °C reduced the capacity to 1.6 equiv./kg; four days at 90 °C reduced the capacity to less than 1 equiv./kg. The thermal stability of the powdered anion resin was markedly less than that quoted elsewhere for anion bead resin. The stability of the floc was also investigated.     

补强填充体系对原位共混型聚丁二烯性能的影响

聚丁二烯橡胶(简称BR)是以丁二烯为单体,采用不同催化剂和聚合方法合成的一种通用合成橡胶的统称,是目前仅次于丁苯橡胶的世界上第二大通用合成橡胶。按照聚合物的微观结构,聚丁二烯     

More meaningful measurement of plastisol properties

The fundamentals of plastisol rheology must be understood in order to properly select and utilize plastisol property measurements. Useful evaluation should also be made of the rheological effects of formulation ingredients and their interrelationships. Other factors such as plastisol preparation, storage conditions, process shear rates, temperatures, dwell times, and finished product specifications will influence the design of effective test procedures. Once meaningful plastisol property measurements have been developed, better quality control assurance results, and in addition quality, productivity, and profitability improvements are effected.     

两种驱油用两亲聚合物复配对其乳化性能的影响

利用稳定性分析仪和光学显微镜研究了B型和海博Ⅲ型2种驱油用两亲聚合物复配对其乳状液稳定性和乳化效果的影响;采用流变仪、界面张力仪和电位分析仪研究了该2种驱油用两亲聚合物及其复配体系的流变性能和界面特性。结果表明:2种驱油用两亲聚合物及其复配体系均能形成O/W型乳状液,随着B型两亲聚合物复配量的增加,复配体系乳状液粒径介于2种两亲聚合物单独形成的乳状液粒径之间,且逐渐减小,分布变窄;其外相体系的黏度、油/水界面张力和Zeta电位的绝对值均呈现先降低后升高的趋势;综合作用下,复配体系乳状液液滴的迁移速率降低,絮凝、聚并程度先升高后降低;相比于2种驱油用两亲聚合物单独使用时,复配体系乳状液的稳定性呈现先降低后升高的趋势,并最终将其超越。     

微波固相法合成苯并恶嗪及其共混树脂的性能

邻位二烷基取代苯胺与苯酚和多聚甲醛经100 W微波辐照20 min反应得到了5种苯并恶嗪单体,将其中邻位为甲基和乙基取代的苯胺型苯并恶嗪与双酚A型苯并恶嗪(BAF)共混,采用红外光谱(FT-IR)、核磁共振氢谱(1H-NMR)、示差扫描量热仪(DSC)、动态机械分析(DMA)、热失重分析仪(TGA)、粘度仪和介电阻抗仪研究了共混树脂的粘温性、热性能及介电性能。结果表明,邻二甲基苯胺型苯并恶嗪(2m6m-BZ)与BAF以物质的量比3∶7共混的体系100～250℃下粘度<500 mPa.s,其固化后热性能接近固化后的纯BAF树脂,且介电常数<3.9,介电损耗低于0.003 5,优于其它共混树脂。     

The effect of network structure on moisture absorption of epoxy resins

An investigation of the effect of modifying the network structure on moisture absorption of epoxies was performed. The network was modified by crosslinking the epoxides with various mono/diamine proportions, resulting in decreasing density and increasing free volume. It was discovered, however, that concomitant effects, i.e., the formation of a two-phase structure, and changes in resin polarity and in resin–water affinity predominated. Thus, compositions with higher chain molecular weights between crosslink points yet exhibited lower diffusion coefficients. Also, when drastic swelling conditions (such as a water-boil treatment) were employed, moisture absorption was facilitated by penetration via newly formed microcracks.     

复合分散体系对聚氯乙烯树脂颗粒特性的影响

以三氯乙烯模拟氯乙烯(VC),考查聚乙烯醇(KH20)/羟丙基甲基纤维素(60SH50)复合分散剂的分散能力和保胶能力,发现分散能力和保胶能力均随分散剂用量的增加而提高;复合分散剂中KH20比例增大,分散能力下降而保胶能力增强。以此为基础进行VC悬浮聚合,研究分散剂对聚氯乙烯(PVC)树脂颗粒特性的影响。发现适量的分散剂可同时提高PVC树脂的表观密度和增塑剂吸收量;增大KH20的比例可提高PVC树脂的表观密度,同时使粒度分布变窄,但是增塑剂吸收量有所下降。     

不同硫化体系氯化聚乙烯/再生胶并用胶性能研究

本研究改变CM橡胶的硫化体系种类,研究了TCHC硫化体系,PT75和促903硫化体系,ECHO.A和促808硫化体系对氯化聚乙烯/再生胶共混硫化胶硫化特性、力学性能和耐热老化性能的影响。结果表明：三种硫化体系的并用胶的硬度和老化前后的拉伸永久形变基本保持不变。PT75和促903硫化体系的拉伸强度、撕裂强度和100%定伸应力最高;ECHO.A和促8 0 8硫化体系的扯断伸长率最低;老化后,T C H C硫化体系的拉伸强度最高,P T 7 5和促9 0 3硫化体系的扯断伸长率最低,PT75和促903硫化体系的100%定伸应力最高。     

耐热PVC增塑糊的研究

通常的PVC糊树脂热分解温度为160℃,从其流变特性出发筛选了各种热稳定剂及其他助剂,研究出比原来分解温度高出40~50℃PVC增塑糊制备方法,使其应用在热浸渍制品上,不仅保持原PVC增塑糊的一些性能,而且耐热性、透明性、附着力等都有新的改进,因而获得了良好的经济效益。     

聚氯乙烯塑溶胶的"湿碰湿"技术

介绍了国外聚氯乙烯塑溶胶的“湿碰湿”技术,即在前一道涂层未经烘干的状态下直接进入下一道涂装工序,减少了烘烤的次数,并确保了各道涂装工序的质量与效果。     

Viscosity aging of poly(vinyl chloride) plastisol: The effect of the resin type and plasticizer type

The viscosity of freshly prepared poly(vinyl chloride) (PVC) plastisol increases with time, and this phenomenon is called viscosity aging. The increase is rapid in the beginning and slows down to a quasistable value, but a very slow increase continues. The phenomenon may be a result of either the deagglomeration of agglomerated particles or the dissolution of low‐molecular‐weight PVC into the plasticizer. In this work, two typical commercial resins were used, one containing friable agglomerates and the other containing nonfriable agglomerates. With the friable‐agglomerate resin, about 40% of the initially present agglomerates deagglomerated, whereas the viscosity increased in a week to twice the initial value. With the nonfriable‐agglomerate resin, very fine and very low molecular weight particles, about 3% of all the particles, dissolved into the plasticizer in 2 days. The effect of the plasticizer type on the viscosity aging through deagglomeration was investigated with four plasticizers and three plasticizer blends. The emulsifiers used for polymerization, and retained through drying, affected the aging in the beginning. On the other hand, the viscosity after 1 week was free from the effect of the emulsifier and was affected only by the plasticizer type. With the exception of two blends, the 1‐week viscosity was quantitatively related to the dielectric constant divided by the molecular weight of the plasticizer. For the plasticizer blends, one of the plasticizers could have a dominant effect on the promotion of deagglomeration. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 448–464, 2005     

The effect of pressure on the curing behavior of unsaturated polyester resins

The effect of pressure on the curing behavior of unsaturated polyester resin was investigated, both experimentally and theoretically. The resin used was a general-purpose unsaturated polyester resin and the initiator used was t-butyl perbenzoate. A series of isothermal runs with differential scanning calorimetry (DSC) were made at various levels of cure pressure. It was found that the rate of cure was retarded under pressure, and that the ultimate degree of cure went through a maximum at a certain pressure as the cure pressure was increased from atmospheric pressure to 6.21 MPa (900 psi). It was interpreted that pressure has two competing effects on the curing behavior of unsaturated polyester resin; one is a free volume effect that hinders the curing reaction and the other is a thermodynamic effect that favors it. Therefore, when the pressure is higher than a certain level, the free volume effect becomes predominant over the thermodynamic effect, the ultimate degree of cure diminishing as the cure pressure is increased beyond that level. Theoretical interpretation of the experimental results is given, using a mechanistic kinetic model developed in our previous publication.     

提高PVC塑溶胶粘合力研究

ＰＶＣ塑溶胶配制的密封胶具有单组分、无溶剂、贮存稳定及弹性好、耐化学介质优良等特点、缺点是粘合力差。本文介绍了环氧树脂、聚氨酯树脂、聚酰胺树脂、丙烯酸树脂、尿素树脂等对ＰＶＣ塑溶胶的增粘作用,论述探讨了增粘剂的结构特点和增粘机理,以及油面胶的配制。