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。     

十二烷基硫酸钠碳链分布对PVC糊树脂特性的影响

采用不同种类的市售十二烷基硫酸钠作为乳化剂生产PVC糊树脂,研究了十二烷基硫酸钠的碳链分布对PVC糊树脂粒度分布、糊黏度(B式)、72 h增稠率以及标准糊S流动性的影响,设计出适合PVC糊状树脂生产的配方。     

储存温度对PVC溶胶黏度性能的影响

采用不同类型的糊树脂制备聚氯乙烯(PVC)溶胶,研究了各种PVC溶胶在不同储存温度下的黏度性能。结果表明:50℃以下时,随储存温度升高,各种PVC溶胶黏度降低。储存温度在25～40℃时,PVC溶胶的黏度较小且稳定性较好,有利于产品加工。微悬浮法制备的PVC溶胶不宜用于低温季节或是寒冷地区,种子乳液法制备的PVC溶胶树脂可用于高温环境或是温差较大的季节和地区。     

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。     

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。     

微悬浮法聚氯乙烯糊树脂流变性能影响因素分析

采用旋转流变仪测试微悬浮法聚氯乙烯糊树脂的流变性能,重点分析了聚氯乙烯糊树脂的颗粒形态、粒度分布、分子质量及其分布对流变性能的影响。     

掺混树脂对PVC增塑糊性能的影响

采用PVC糊树脂与掺混树脂复配,研究各复配比例下,掺混树脂对增塑糊初始黏度及黏度稳定性、以及糊制品蒸发残渣性能的影响。结果表明:增塑糊初始黏度随掺混树脂比例的增加而逐渐减小;各体系糊黏度稳定性也相应变差,当CPM-31/SB-100=70/30时,PVC增塑糊的黏度稳定性最差,而CPM-31/SB-100=100/0时的黏度稳定性最好;掺混树脂的加入主要影响PVC糊制品在4%乙酸和正己烷浸泡溶剂下的蒸发残渣性能指标,且当掺混树脂含量为10份后两者残渣结果变化趋势相反。     

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。     

填料类型对PVC溶胶凝胶塑化流变性能的影响

采用振动黏度计和旋转流变仪研究了不同填料制备的聚氯乙烯(PVC)溶胶的黏度随温度或时间的变化情况。结果表明,随温度升高或时间延长,不同填料填充PVC溶胶的黏度呈先降低,后由缓慢升高至快速升高,形成一个肩峰并达到一个最大值,最后又逐步变小的非正态分布趋势。用旋转流变仪可将PVC溶胶的凝胶塑化流变行为完整表征出来,是一个更为有效的方法。加入填料使得PVC溶胶的黏度增大,凝胶过程加快,主要与填料粒径及形貌有关。是否添加填料以及填料类型对PVC溶胶相应的形态转变温度和时间没有影响。     

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.     

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.     

树脂复配对PVC增塑糊黏度及稳定性的影响

采用相同生产工艺、不同聚合度的两种树脂进行复配,研究各复配比例下聚氯乙烯增塑糊初始黏度以及黏度随时间的变化情况。结果表明,当高聚合度糊树脂PSH-10与低聚合度糊树脂CPM-31的配比为20/80时,糊黏度在各时间段最低;当PSH-10/CPM-31=50/50时,糊黏度稳定性最差;高聚合度糊树脂PSH-10基体中引入低聚合度糊树脂CPM-31（CPM-31含量小于50 %）时,对增塑糊黏度的影响要比低聚合度糊树脂CPM-31中引入高聚合度糊树脂PSH-10（PSH-10含量小于50 %）的影响明显;聚合度分布宽不利于增塑糊黏度稳定性。     

Effects of paste resins on the foaming properties of PVC plastisols

This article studies the foaming properties of PVC plastisols prepared from six different types of PVC paste resins with different degrees of polymerization that were produced through two methods, a seed emulsion method and a micro-suspension method. The underlying mechanisms that result in differences in the foaming properties are discussed as well. The results indicate that formulation S5 has the best foaming quality using past resins produced with the seed emulsion method, and formulation S6 made the best plastisol samples from paste resins produced through the micro-suspension method. Seed emulsion-produced paste resins with low degrees of polymerization are more suitable for preparing high-quality foam materials. The parameters used to judge the foam quality are the initial decomposition temperature T_f (5%), T_f − Tη_max and T_f (5%) − Tη_max. The greater the value of these three parameters, the better the foaming effect. The degree of polymerization of the paste resin and the particle morphology directly affect the rheological parameters, namely Tη_max, of PVC plastisol, and subsequently affect the magnitude of T_f − Tη_max and T_f (5%) − Tη_max, which in turn affect the quality of the foam.     

Soft PVC foams: Study of the gelation,fusion, and foaming processes. I. Phthalate ester plasticizers

The use of foamed plastics gains more and more interest every day. Flexible poly(vinyl chloride) (PVC) foams have excellent mechanical properties and low price, thus their application is extensive. Foams are produced from plastisols, which are based on the suspension of the PVC resin in a plasticizer. Phthalates are the most used plasticizers in flexible PVC foam formation. In this study, we have studied the influence of the phthalate ester‐type plasticizers on the foaming process and the quality of the foams obtained from the corresponding plastisols. For the plastisols prepared with the nine phthalate plasticizers considered, we have studied and discussed the complex and extensional viscosities; the thermal behavior (DSC) including the decomposition of the chemical blowing agent, and the foam production by rotational molding. In addition, we have characterized the foams obtained by thermomechanical analysis, density, and bubble size distribution. As expected, clear correlations have been obtained between the molecular weight and structure of the plasticizer with the rheological behavior of the plastisols. The knowledge of the gelation and fusion processes and evolution of the extensional viscosity of the plastisols combined with the study of the thermal decomposition of the blowing agent in each plastisol allows for better understanding of the complex dynamic behavior of these foaming systems. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Extensional viscosity measurements and characterization of poly (vinyl chloride‐co‐vinyl acetate) plastisols and foams

The foaming of PVC‐VA [Poly (vinyl chloride‐co‐vinyl acetate)] plastisols is a complex combination of processes involving the simultaneous curing of the paste with the evolution of gases caused by the decomposition of the chemical blowing agent. The extensional viscosity is a fundamental characteristic of the material, responsible for the behavior of the system when undergoing the extensional stress produced by the released gases. Nevertheless, such changes have not been considered to the same extent as the complex viscosity evolution or the thermal processes suffered by PVC‐VA plastisols. The objective of the present work is to study the extensional viscosity of the PVC‐VA plastisols prepared with three plasticizers of similar structure, but with different curing and rheological behavior in order to investigate its influence on the quality of the foams obtained. Extensional viscosity measurements under forced prestretch conditions revealed that depending on the structure and consequently on the compatibility of the plasticizer used, each plastisol develops its properties and structure accordingly. DINCH plasticizer (Diisononyl cyclohexane‐1,2‐dicarboxylate presenting alicyclic ring) seems to be the less compatible compared with the other two studied (both presenting aromatic rings) according to its behavior during the curing and foaming processes and may not be able to withstand the pressure evolved by the released gases during the foaming process yielding foams of poorer quality. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Plasticizer factors influencing take-up by PVC resins

The ease with which plasticizer is combined with poly(vinyl chloride) resin is a measure of processing characteristics critical in the dry blending of suspension PVC and the gelation of plastisols. By using commercial grade plasticizers, this study developed predictive equations for the following processing parameters of dialkyl phthalates in PVC:

• Relative dry-blend rates in suspension PVC as a function of plasticizer viscosity.
• Relative initial gelation temperatures in plastisols as a function of plasticizer molecular weight and solvating strength.
• Relative final gelation temperatures in plastisols as a function of plasticizer solvating strength.

This information allows one to predict the relative processing characteristics of any dialkyl phthalate plasticizer for PVC on the basis of its chemical and physical properties.