马来酸酐接枝改性氯化聚氯乙烯的制备及其在PVC中的应用

采用固相法制备马来酸酐接枝氯化聚氯乙烯(CPVC-g-MAH),得到了接枝率达2.91 %的CPVC-g-MAH,并对其进行了性能测试,探讨了聚氯乙烯(PVC)/CPVC-g-MAH共混物的冲击性能和加工性能,与PVC/氯化聚氯乙烯(CPVC)共混物进行对比以观察改性效果。结果表明,CPVC-g-MAH的热性能较CPVC有较大提高;PVC/CPVC-g-MAH共混物的冲击性能比PVC/CPVC共混物有所提高,而平衡转矩有所降低,说明CPVC-g-MAH相比于CPVC对PVC共混物加工性能改善效果更加明显。     

Polycaprolactone as a permanent plasticizer for poly(vinyl chloride)

Polycaprolactone at moderate usage levels has been determined to provide desirable modifications of both rigid and plasticized poly(vinyl chloride). In rigid PVC it effected significant improvement in melt processing as well as good modulus, tensile strength, and kerosene resistance. Impact strength was not measurably altered, but heat-distortion temperature was appreciably lowered. In flexible PVC, polycaprolactone contributed increased tensile strength and ultimate elongation, reduced volatility, and kerosene extraction. Lowering of modulus and flex temperatures were similar to conventional liquid polymeric plasticizers, but melt processability was not as good as lower-molecular-weight plasticizers.     

Melt extensiometer investigation of PVC pipe compounds

The Rheotens melt extensiometer can be a valuable tool for developing and studying rigid polyvinyl chloride compounds. The Rheotens can relate effects of variables such as processing aids, lubricants, and extrusion conditions on compound extrusion characteristics and changes in the melt on a morphological and molecular level, adding to the understanding of the processing and physical properties development of PVC materials.     

In-depth rheological study of acrylic processing aids in rigid polyvinyl chloride applications

Acrylic processing aids are used widely in rigid polyvinyl chloride (PVC) applications. Key functions of processing aids in terms of processing and performance are discussed in the paper. Effect of molecular weight of acrylic processing aids on their functions are studied. Additionally, effect of processing conditions, such as temperature and shear on fusion characteristics of PVC formulations are investigated. Shear rate in the processing was varied by means of rotor speed in torque rheometer. Processing aids of comprehensive molecular weight range are evaluated in the study. It was observed that relatively lower molecular weight processing aids have different response to change in shear and temperature than higher molecular weight processing aids. Depending upon fusion conditions PVC formulations can yield either a single or double fusion peak. Generally, it was considered that ultra-high molecular weight processing aids yield a double fusion peak, however, it was demonstrated in the studies that it is not true. Fusion conditions, temperature, and shear are the main driving forces of fusion dynamics, resulting in either a single or double fusion peak. Relatively low molecular weight acrylic processing aids can also yield double fusion peak. Melt viscosity and shear thinning properties are also examined. Relatively lower molecular weight processing aids showed higher shear thinning behavior. Effect of temperature and shear on degree of fusion was studied. It was shown that optimum processing parameters can increase the degree of fusion by ~10%.     

Understanding the functions of acrylic processing aids in rigid PVC injection molding

Poly(vinyl chloride) (PVC) compound use is growing in specialty injection molding applications such as appliances, business equipment, and electrical enclosures. A key factor in determining the appearance and physical properties of the molded parts is the processability of the PVC compounds, which can be improved through the use of acrylic processing aids. Processing aids promote PVC fusion, modify the melt rheology, and/or provide lubrication. Some processing aid products are designed to serve one of these functions while others provide a combination of functions. Each of these functions and its major benefits in rigid PVC injection molding are described. Some guidelines for selecting appropriate processing aid products for applications are provided.     

Processing aids for poly(vinyl chloride)

Processing aids are an important class of additives for poly(vinyl chloride) (PVC). At relatively low concentration, processing aids enable the melt processing of rigid PVC and enlarge its processing windows. Discussed in this presentation are some major functions of processing aids, such as promoting PVC fusion, modifying PVC's melt rheology, and lubricating to prevent adherence of PVC melt to the processing equipment. Some examples are given to show the effects of processing aids on PVC die swell, melt fracture, melt viscosity, and PVC fusion. Commercial sources of various processing aids and typical PVC formulations for various applications are also discussed.     

Rheological and mechanical properties of poly(vinyl chloride)/chlorinated poly(vinyl chloride) miscible blends

The properties of poly(vinyl chlorlde)/ehlorinated poly(vinyl chloride) (61.6 percent C1) blends, prepared by melt and solution blending, were measured by various tests. Based on the chlorinated poly(vinyl chloride) (CPVC) composition, percent chlorine, and mole percent CC1₂ groups, these blends were expected to show intermediate properties between miscible and immiscible systems. Indicative of miscible behavior were the single glass transition temperatures over the entire composition range for both melt and solution blended mixtures. A single phase was also indicated by transmission electron microscopy. However, the yield stress showed a minimum value less than either of the pure components in the 50 to 75 percent CPVC range, which is characteristic of two-phased systems. Specific volume, glass transition temperature, and heat distortion temperature were linear with binary composition. The storage modulus showed a small maximum, suggesting a weak interaction between the two miscible polymers. Heats of melting for the residual PVC crystallinity were also less than expected from linear additivity. At 160°C and 210°C, the logarithm of the complex viscosity was essentially linear with volume fraction of CPVC, except for a very slight decrease in the 50 to 75 percent CPVC range, which may have been a result of lower crystallinity. At 140°C, the complex viscosity of the CPVC was less than that of PVC owing to the higher crystallinity of the latter. The viscosities were similar at 160°C, but at 210°C, where most of the crystallites had melted, the complex viscosity of the CPVC was higher because of its higher glass transition temperature.     

苯乙烯氯化原位接枝改性氯化聚氯乙烯的研究

采用氯化原位接枝技术在聚氯乙烯（PVC）进行氯化反应的同时接枝上各种不同单体．从而制备改性的氯化聚氯乙烯（CPVC）。研究了PVC固相法氯化原位接枝St的规律，讨论了单体苯乙烯（St）加入量、氯含量对产物物理力学性能及流变性能的影响。结果表明：St的加入量为10份时，改性CPVC的屈服强度明显高于空白CPVC的屈服强度，但维卡软化点降低；改性CPVC的屈服强度和维卡软化点均随氟含量增加而增大；St的加入量适当，可以同时提高改性CPVC的屈服强度和冲击性能，降低熔体粘度。     

New ultra high molecular weight acrylic processing aids for rigid PVC foaming

Foaming of rigid polyvinyl chloride (PVC) is studied as a function of high molecular weight acrylic processing aids. The industrial process to evaluate quality of foam is discussed in detail. The role of acrylic processing aids to improve melt strength and hence foaming of PVC is explained. It is demonstrated that increase in molecular weight of acrylic processing aids increases its effectiveness. It is found that ultra-high molecular weight processing aids is 25%–30% more efficient than relatively lower, but still high, molecular weight acrylic processing aids. The higher molecular weight processing aids provided comparable foaming performance at lower loading levels. Foaming reduced the density of PVC compounds to 0.32–0.34 g/cm³. More than 1000% expansion is achieved in the melt extrusion process using a chemical blowing agent. Fusion characteristics are also studied. Fusion times for initial fusion peaks are in the range of 42–44 s while the fusion times of the second fusion peaks are in the range of 74–94 s. The higher molecular weight processing aids maintained fusion characteristics of PVC compounds, warranting no significant changes in commercial process.     

Effects of postchlorination on key product and processing properties of PVC

The behavior of PVC resins has been shown to change dramatically when postchlorinated from 57 to 70 percent chlorine. Many of these changes are beneficial: heat resistance, thermoformability, and combustion properties are improved to an extent that opens new market opportunities for properly formulated chlorinated PVC (CPVC) materials. Sharply increasing melt viscosity also results from increasing chlorine content, creating the need for compounding and processing expertise differing from that for rigid PVC. The fact that such expertise has been developed, and is constantly being improved, is expanding the use of CPVC.     

PB橡胶粒径对CPVC/PVC/ABS共混体系结构与性能的影响

采用乳液聚合技术合成了一系列不同PB橡胶粒径的ABS核壳改性剂,将其与CPVC、PVC共混,考察了CPVC/PVC/ABS共混物的结构与性能。动态力学分析表明：CPVC与PVC比例为90/10时,CPVC/PVC共混物部分相容,CPVC/PVC/ABS共混物也是部分相容;扫描电子显微镜分析其形态结构表明：共混物中ABS分散受PB橡胶粒径影响,PB橡胶粒径为113 nm的ABS在CPVC中分散最均匀。力学性能测试表明：随着PB橡胶粒径的增加,共混物的冲击强度先增大后减小,拉伸强度并无明显变化。     

Improved CPVC compounds: Miscible alloying with styrenic copolymers

Previous studies of PVC with styrene/maleic anhydride (SMAnh) copolymers showed miscibility or single phase morphology, but only at very low blended proportions of 10:1. At higher blend proportions this alloy system separated into two altered phases, neither being a pure component. Unlike PVC/SMAnh alloys, chlorinated poly(vinyl chloride) (CPVC) SMAnh systems show total miscibility for all blended proportions. The effects of alloying CPVC resins with SMAnh copolymers is the subject of this report. Using DSC and DMA miscibility of these systems are examined. Effects of SMAnh levels in these alloys on heat resistance, melt viscosity, processability, and flame retardance are assessed.     

ACR对PVC加工性能的影响

详细研究了丙烯酸酯类PVC加工助剂———ACR的特性黏度、组成对PVC共混物加工性能的影响。结果表明,随着甲基丙烯酸甲酯用量的下降和丙烯酸丁酯用量的提高,其塑化速度增大,但熔体强度降低,在组成相同的情况下,特性黏度越大,塑化越慢,熔体强度越大;丙烯酸酯类加工助剂对PVC制品的拉伸强度和维卡软化点无明显影响,高黏度的加工助剂有提高PVC制品拉伸强度和维卡软化点的趋势。     

氯化聚氯乙烯的生产工艺与市场现状

介绍了氯化聚氯乙烯的国内外应用、生产工艺、市场现状,国内使用的PVC若有1％用CPVC代替,国内CPVC需求量将达到2万t/a,因此氯化聚氯乙烯具有广阔的市场前景。氯化聚氯乙烯是氯碱厂吃氯的下游产品,生产CPVC既可充分利用现有的PVC生产装置,又可充分发挥烧碱装置的生产能力,因此氯化聚氯乙烯是国内氯碱厂可以大力开发的产品。     

PVC-C/PVC共混材料的性能研究

采用氯化聚乙烯（CPE）对氯化聚氯乙烯（PVC—C）进行抗冲改性,将改性后的PVC—C与PVC进行共混,研究了PVC-C／PVC配比对PVC-C／PVC共混物力学性能、耐热性能及流变形能的影响。结果表明,PVC—C／PVC共混物的维卡软化点随PVC—C的用量增加而上升,在50／50（质量比）处有一拐点,大于50／50时上升更快些。共混物的拉伸强度、弯曲强度和熔体黏度随PVC—C用量的增加而提高;混物中随PVC—C用量增加,塑化时间缩短,塑化能力增强,而冲击强度和断裂伸长率却随PVC—C用量增加而下降。共平衡转矩增加。     

国内外氯化聚氯乙烯生产技术比较

通过探讨水相悬浮法氯化PVC的反应机制和表征CPVC样品,分析了国内外CPVC生产技术差距,指出专用PVC的聚合工艺是影响CPVC质量的关键因素,提高PVC及CPVC树脂的分析表征手段是CPVC发展的重点。     

PA氯化接枝改性CPVC流变行为的研究

采用氯化原位接枝法制备改性CPVC,在氯化的同时加入丙烯酸丁酯(BA)得到CPVC-g-PBA,利用毛细管流变仪研究了CPVC和CPVC-g-PBA的流变行为,讨论了两者的剪切应力和剪切速率以及温度对熔体流变行为、熔体粘度的的的影响,并测定了其非牛顿指数。     

Graft‐modified HCPE with methyl methacrylate by the mechanochemistry reaction. II. Physical‐mechanical properties and processability

In this article, the physical‐mechanical properties and processability of graft‐modified highly chlorinated polyethylene (HCPE; chlorine contents: ≥ 60%) with methyl methacrylate (MMA) by mechanochemistry reaction were studied. The results showed that the HCPE‐g‐MMA system is superior to unmodified HCPE in physical‐mechanical properties, particularly in processability. In addition, the HCPE‐g‐MMA system, with about 62% chlorine content, was the same as PVC in its physical‐mechanical properties. The HCPE‐g‐MMA system, with about 65.5% chlorine content, is the same as chlorinated poly(vinyl chloride) (CPVC) in its physical‐mechanical properties, except that the Vicat softening temperature and processability of HCPE‐g‐MMA system are superior to PVC and CPVC. Compared with PVC and CPVC, the HCPE‐g‐MMA system proves better due to its lack of a toxic monomer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 282–287, 2004     

Effect of additives on the melt elastic modulus of rigid poly(vinyl chloride) formulations

A factorial experiment shows that calcium stearate and paraffin wax significantly decrease the melt elastic modulus of rigid poly(vinyl chloride) formulations. It is also concluded the melt elastic modulus of PVC is not significantly affected by the presence of methyltin stabilizer, acrylic processing aids or polyethylene wax. The only significant interaction found was that between temperature and concentration of paraffin wax. A regression model was derived for shear storage modulus (G′) at a deformation frequency of 100 radians/sec. No significant correlation between G′ and critical shear rate for melt fracture was discernable.     

PVC/M-80共混体系的流变性能研究

本文采用高压毛细管流变仪及HAKKE转矩流变仪对PVC/M-80共混体系的流变性能进行了研究。探讨了原料组分比,以及加工工艺参数对PVC/M-80共混体系流变性能的影响。结果表明,PVC/M-80共混体系熔体是典型的非牛顿假塑性流体;随着M-80组分比的增加,共混体系熔体的平衡扭矩和熔体温度均呈明显的降低趋势;共混体系熔体的平衡扭矩随加工温度的增加呈线性降低;在常用加工转速范围内,转速对共混体系流动性的影响不明显。