碳酸钙对PVC增塑糊黏度及稳定性的影响研究

采用振动黏度计系统研究了碳酸钙粒径大小、含量及颗粒形貌对环保聚氯乙烯（PVC）增塑糊黏度及稳定性的影响规律。结果表明,用4.5um碳酸钙配制的增塑糊初始黏度最大,且黏度稳定性最差;固定PVC树脂为100份时,随碳酸钙含量的增加,增塑糊的初始黏度增大,黏度稳定性降低;固定PVC和碳酸钙粉体总量为120份时,随碳酸钙含量的增加,增塑糊的初始黏度减小,黏度稳定性升高;用规则菱形碳酸钙配制的增塑糊黏度相对较小,用棉絮状碳酸钙配制的增塑糊黏度相对较大,且黏度稳定性最差。     

PVC分子量及分布对增塑糊黏度性能的影响

研究了几种生产工艺聚氯乙烯(PVC)糊树脂分子量及分布对增塑糊黏度及稳定性能的影响。结果表明:相同颗粒形态糊树脂中,分子量越大,黏度越小,分子量大小与增塑糊存放稳定性无明显规律;分子量大小比聚合度更能反映与增塑糊黏度的对应关系。     

PVC增塑糊黏度及其稳定性正交实验研揪

采用L9(34)正交实验设计,研究PVC类型、填充剂粒径大小,硅油种类和用量多个因素对PVC增塑糊黏度及其稳定性的影响.实验结果表明:初级粒子粒径较大、表面较规则的微悬浮法糊树脂制得的增塑糊初始黏度最小,黏度稳定性较好;填充剂粒径大小与PVC增塑糊黏度成正比,粒径越大,糊初始黏度越大,粒径大小对糊的稳定性影响大致相同;100 mPa·s硅油体系下增塑糊初始黏度较低,50 mPa·s硅油体系下糊黏度稳定性较好;硅油加入0.6份时糊初始黏度较低,0.4份时糊黏度稳定性较好.     

PVC增塑糊黏度及其稳定性正交实验研究

采用L9（3^4）正交实验设计，研究PVC类型、填充剂粒径大小，硅油种类和用量多个因素对PVC增塑糊黏度及其稳定性的影响。实验结果表明：初级粒子粒径较大、表面较规则的微悬浮法糊树脂制得的增塑糊初始黏度最小，黏度稳定性较好；填充剂粒径大小与PVC增塑糊黏度成正比，粒径越大，糊初始黏度越大，粒径大小对糊的稳定性影响大致相同；100mPa·s硅油体系下增塑糊初始黏度较低，50mPa·s硅油体系下糊黏度稳定性较好；硅油加入0．6份时糊初始黏度较低，0．4份时糊黏度稳定性较好。     

PVC糊树脂颗粒特性对增塑糊陈化行为的影响

选用5种不同牌号的PVC糊树脂制备出增塑糊,研究了PVC糊树脂的颗粒特性对增塑糊陈化行为的影响。结果表明:①小粒子可填充在大粒子之间,从而降低增塑剂的填充量,自由增塑剂更多,成糊后初始黏度较低;②与紧密型糊树脂相比,松散型糊树脂的增塑糊黏度稳定性更好;③分子质量越大,真实密度越大,增塑糊黏度稳定性越好;④对于紧密型糊树脂,低黏度的增塑糊在陈化过程中大粒子会发生沉降,导致糊中粒子分布不均一。     

PVC糊树脂颗粒形态研究

用扫描电镜结合粒度分析方法,研究了微悬浮法和种子乳液法PVC糊树脂颗粒形态特征,并探讨了颗粒形态与增塑糊黏度之间的关系。     

聚氯乙烯糊树脂粉料与增塑糊性能关系——调节糊粘度的可能性

本文阐述了聚氯乙烯糊树脂的颗粒结构特征,喷雾干燥和后处理的条件对糊树脂颗粒粒径分布与树脂粉料在增塑剂中解碎难易的影响以及不同增塑糊的流动性能;提出了控制糊粘度的可行性;建立了掺混增塑糊糊粘度计算的经验公式和胶乳粒子准单峰分布的增塑糊牛顿型高剪切极限粘度的数学模型。     

表面活性剂对PVC增塑糊稳定性能的影响及机理探讨

研究表面活性剂种类、用量对PVC增塑糊黏度稳定性的影响,并探讨增塑糊的稳定机理.结果表明:吐温类表面活性剂改性PVC糊初始黏度最大,350η硅油次之,聚氧乙烯类表面活性剂改性的增塑糊初始黏度最小,其中350η硅油改性的增塑糊黏度稳定性最好.随表面活性剂用量的增多,增塑糊的初始黏度越小,但增塑糊的稳定性与表面活性剂用量并不存在简单的线性关系.对有表面活性剂存在的PVC增塑糊,主要遵循空间位阻稳定机制和空位絮凝机制.     

劳保手套用高粘度树脂加工性能研究

通过研究糊树脂粒子的粒径、粒径分布以及表面形态等影响增塑糊流变性能的因素,探讨劳保手套用高粘度糊树脂的加工性能。     

不同生产方法糊树脂复配对PVC增塑糊黏度及稳定性的影响

采用相近聚合度、不同生产方法的两种树脂进行复配,研究各复配比例下增塑糊黏度及稳定性。结果表明：当微悬浮法糊树脂1与MSP-3法糊树脂2的配比为80/20时,糊黏度大且稳定性最差;当树脂1/树脂2 =50/50时,糊黏度较低,稳定性最好。树脂1中引入树脂2（含量小于50 %）使得体系黏度上升,黏度稳定性也变差,糊树脂颗粒形貌的影响比粒度分布的影响更大;树脂2中引入树脂1（含量小于50 %）可降低其黏度和提高黏度的稳定性,主要是糊树脂颗粒形貌和粒度分布优化的原因。     

树脂类型对PVC溶胶流变性能的影响

研究了不同生产方法糊树脂制备的聚氯乙烯（PVC）溶胶,在旋转流变仪程序升温模式下的流变性能。通过扫描电子显微镜、激光粒度仪和凝胶渗透色谱仪研究了PVC糊树脂的颗粒形貌、粒度及分布以及相对分子质量及相对分子质量分布特征,从而建立了PVC溶胶流变性能参数与糊树脂特性参数间的关系。结果表明,随着温度的升高,PVC溶胶的储能模量、损耗模量和复数黏度等流变参数呈非正态分布变化趋势,可分为4个阶段：前三阶段,流变参数先降低,后由缓慢升高至急速升高,形成一个肩峰并达到一个最大值,黏度变化趋势与树脂颗粒形态有关;第四阶段,流变参数逐步变小,黏度主要受树脂相对分子质量及相对分子质量分布的影响。     

Plastisols of poly(vinyl chloride); particle size distribution,morphology, rheology,and mechanism of aging

Plastisols of poly(vinyl chloride) (PVC) are suspensions of fine resin particles in plasticizer with about a 50% resin volume fraction. Typically, the gross particle size ranges from about 15 to 0.2 μm and smaller, where the common practice of spray drying these resins dictates that the size ranges include agglomerates as well as the ultimate particles. In this work we have related the particle size distribution to the dynamic mechanical behavior with model plastisols prepared from various particle-size fractions of a commercial resin. This relationship, together with the microscopic observation of the particle dispersions, provided an interpretation of the plausible mechanisms of the viscoelastic response. The morphological observation of the particle aggregates, the changes of the particle size distribution during the aging, and the above viscoelastic study have established that deagglomeration is the dominant cause of the increase of viscosity during aging.     

碳酸钙表面辐照改性及对HDPE／CaCO3体系性能的影响

本文介绍CaCO_3表面的辐照改性以及改性CaCO_3对HDPE/CaCO_3体系性能的影响。通过高能辐照,使CaCO_3表面接上乙烯基单体,形成一层有机膜。由改性CaCO_3和液体石蜡的接触角、吸油率和平均粒径等的测定表明,该有机膜使CaCO_3的亲油性和吸油率提高,对CaCO_3粒径的影响较小。通过改性前后CaCO_3/HDPE体系力学和流变性能的测定可知,由于该有机膜改善了HDPE和CaCO_3之间的相容性,改性体系的拉伸强度和冲击韧性有明显提高,加工流变性能也有所改善,其熔体粘度较低,温敏性较好。     

SiO2/PBA/PMMA和CaCO3/PBA/PMMA核壳结构纳米材料的制备与表征

利用γ 甲基丙烯酰氧丙基三甲氧基硅烷(KH-570)对纳米二氧化硅和纳米碳酸钙有机化处理,红外光谱(FTIR)测试表明,纳米二氧化硅通过有机化处理可以在表面接枝上有机基团,表现在表面处理后波数在2955,2860和1460cm-1有甲基的吸收峰,而纳米碳酸钙由于表面上已有有机基团,表面上没有接枝上新的有机基团。然后利用乳液聚合的方法制备了以表面处理过的纳米二氧化硅或纳米碳酸钙为核,丙烯酸丁酯和甲基丙烯酸甲酯为壳的有机-无机杂化材料。用凝胶渗透色谱(GPC)测定了其各种相对分子质量及其相对分子质量分布后发现,加入纳米碳酸钙后其相对分子质量有所降低,相对分子质量分布变宽;加入纳米二氧化硅后其相对分子质量有所增大,相对分子质量分布变窄。透射电镜(TEM)和粒度分布仪测试表明,乳液聚合前粒子大部分以团聚体的形式存在,粒径在1～2μm左右;乳液聚合后粒子大部分以纳米尺寸存在,粒径10～200nm。实验证明,乳液聚合是制备有机-无机纳米杂化材料非常有效的方法。     

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。     

Gelation and fusion profiles of PVC dispersion resins in plastisols

Poly(vinyl chloride) (PVC) plastisols are used for coatings, films, sheets, foams, and rotational castings. In order to satisfy the requirements for the different applications, a variety of PVC dispersion resins are manufactured. The requirements for the plastisols are many: for example, good air release, viscosity stability, fine particle size, foamability, and good heat stability. Processability is another important requirement, which emphasizes the rheological behavior at room temperature and the gelation—fusion behavior. This paper documents research to fingerprint the gelation and fusion profiles of various PVC dispersion resins. The viscoelastic measurements were used to continuously monitor the changes of moduli during gelation and fusion under a heating rate which simulates the temperature profile of the processes. The effects of molecular weight, resin type, and copolymer on the gelation–fusion behavior are discussed.     

PVC paste rheology: Study of process dependencies

A plastisol is a dispersion (suspension) of fine particles of poly(vinyl chloride) with a plasticizer that is normally applied over a substrate, by spreading or coating, before the gelification and fusion into the final product. Because of the first step, the plastisol rheology study is a very important factor which has to be taken into consideration to determine and fine tune the process conditions. This work is concerned with the study of the rheology of plastisols from selected PVC samples produced by the emulsion process, correlating it with the particle size distribution and surface characteristics from the polymer's powder and modifications during the plastisol aging process. The results obtained show a significant influence of the original polymer properties in the viscosity aging and viscoelastic behaviour of the plastisol. First, a significant decrease in viscosity can be achieved by changing a particular surfactant during the polymerization step. Second, the type of particle aggregates present in the powder, can determine the evolution of the particle size in the plastisol which, in turn, correlates directly with the observed modifications in the aging and viscoelastic behavior. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Changes in rheological properties of polyvinyl chloride plastisols with storage time

In this study, the changes in the rheological curves of polyvinyl chloride (PVC) plastisols with increasing storage time and the factors affecting these changes were studied. The results show that with increasing storage time, all the “viscosity–temperature” and “viscosity–time” rheological curves of PVC plastisols exhibit nonnormal distribution change trends, that is, the viscosity first decreases, and then changes from slow increasing to rapid increasing, forming a shoulder peak, reaches to the maximum value and gradually decreases. With increasing storage time, the complex viscosities of PVC plastisols increased generally in the first, the second, and the fourth stages, and the gelation process shortened in the third stage. The first and second stages of the viscosity changes reflect the “time–temperature” equivalence principle of PVC plastisol in suspension stage. However, the maximum viscosity of PVC plastisol corresponding to temperature Tη_max does not change with increasing storage time.