硬质PVC发泡制品的配方设计

阐述了硬质PVC发泡制品配方中PVC树脂和热稳定剂、发泡剂、优泡剂、冲击改性剂、加工改性剂、填充剂、润滑剂及成核剂等助剂的选用原则,介绍了生产优质硬质PVC发泡制品的基础配方。     

成核剂对PVC涂覆制品泡孔形态的影响

选择不同拓扑结构的无机成核剂纳米二氧化硅和有机蒙脱土,研究其对PVC增塑糊涂覆发泡制品泡孔形态、结构的影响。通过扫描电子显微镜(SEM)观察样品泡孔形态,采用图像分析手段计算泡孔直径、发泡倍率及泡孔密度,以探明成核剂对泡孔形态结构的影响规律及机制。结果表明:与大多数聚合物熔融体系物理发泡不同,球型纳米二氧化硅对偶氮二甲酰胺(AC发泡剂)主导下的PVC增塑糊涂覆工艺化学发泡过程影响不明显,而插层、团聚分散于PVC增塑糊发泡体系中的有机蒙脱土会增加涂覆制品的泡孔直径,并降低发泡倍率及泡孔密度。     

口模压力对微发泡PVC板材泡孔结构及力学性能的影响

以超临界CO_2为发泡剂,使用单螺杆挤出发泡机制备了微发泡PVC发泡板材。研究了口模压力对微发泡PVC板材泡孔结构、力学性能及制品密度的影响。研究发现:增加口模压力有利于增加泡孔密度,提高PVC发泡板材的力学性能,而发泡制品密度则随压力的升高先降低后增加。     

PVC/木纤维微孔发泡技术的研究

国外实验研究已经证明,利用PVC/纤维素纤维复合材料能够产生微孔发泡结构,但发泡率较低.多种因素如PVC、纤维素纤维的改性处理、加工条件等都将影响泡孔形态与制品的物理机械性能.本文针对PVC/木纤维复合材料,研究材料中增塑剂含量、表面改性处理、发泡时间、发泡温度等条件对发泡率、泡孔形态及制品物理机械性能的影响,以建立加工条件、泡孔形态、制品性能之间的关系.     

NBR和PVC共混发泡材料泡孔结构研究

通过调整硫化体系、橡塑并用配比以及发泡剂用量研究其对丁腈橡胶/聚氯乙烯(NBR/PVC)泡孔结构与性能的影响。结果表明,当采用有效硫化体系时,制品的泡孔分布均匀,闭孔率高;当NBR/PVC质量比为50/50时,发泡制品闭孔率较高,泡孔较大,成本较低;模压硫化发泡与自由发泡对比,模压发泡更利于制得较低密度的制品;模压发泡时,发泡制品密度随发泡剂用量的增加而减小。     

超临界二氧化碳发泡软质聚氯乙烯材料的性能研究

采用超临界二氧化碳作为物理发泡剂,进行软质聚氯乙烯(PVC)的发泡试验研究。探讨了实验过程中主要助剂用量对发泡材料的宏观性能和微观泡孔结构的影响。结果表明,当PVC用量为100份,交联剂为0.5份,泡孔调节剂为6份时,发泡材料各项性能较为优异。添加了成核剂纳米Ca CO3后,相比于纯PVC发泡体系,发泡材料的表观密度都有所减小,当成核剂含量为5份时,发泡材料的表观密度最小,为0.294 g/cm3,发泡倍率最大为3.873倍。材料微观的泡孔分布更为均匀,泡孔密度提高到原来的近3倍,泡孔的平均直径较没有添加成核剂的体系缩小了近一半,平均孔径为35.7μm。     

硬质PVC模压低发泡材料的应用

用模压发泡工艺，研究了PVC的低发泡模压成型工艺条件及配方。讨论了加工温度、时间、发泡剂、填充剂、改性剂的种类及用量对PVC泡孔的均匀程度及制品密度的影响。结果表明在合适的加工条件下．发泡剂AC(偶氮二甲酰胺)为0．8份、NaHCO，为0．8份，改性剂PS为8份、0PE为7份。填充剂CaCO3为5份、TiO2为2份时密度达到了0．544g／ml，且泡孔结构良好。     

碳酸钙对PVC低发泡板材成型的影响

探讨碳酸钙在PVC低发泡板挤出加工中,对发泡效果、加工性能及发泡板材料性能等的影响。试验结果表明:碳酸钙的粒径2μm以下,其质量与PVC的质量比为3%~7%时,发泡效果和泡孔质量最佳,发泡制品强度最好。     

软质PVC发泡材料的研究

采用化学发泡一步法模压成型制备了软质PVC发泡材料,研究了发泡剂、泡孔成核剂、改性剂等主要助剂用量对软质PVC发泡材料密度、泡孔结构以及力学性能的影响,并进行了软质PVC发泡材料的配方筛选.结果表明加入吸热发泡剂N能提高发泡体系的发泡效果,降低材料的密度,改善材料的力学性能,当发泡剂AC用量为2份,用量为0.6份时,材料的综合性能优异;当成核剂用量为1份时,体系发泡效果较好;加入粉末NBR不仅能提高发泡材料的断裂伸长率和柔韧性,还可降低发泡材料密度,改善泡孔结构;当NBR用量为20份时,发泡材料密度达到0.44 g/cm3,力学性能优异.     

PVC/木塑发泡复合材料性能研究

实验采用PVC树脂与木粉,加入发泡剂及各种添加剂制得了PVC木塑发泡复合材料,主要研究了木粉粒径、放热型发泡剂偶氮二甲酰胺和吸热型发泡剂碳酸氢钠用量、泡孔调节剂ACR以及加工改性剂MBR用量对复合材料力学性能及材料密度的影响,并通过SEM电镜照片分析对比了单纯使用AC和采用AC与NaHCO3复合发泡时制品的发泡性能及泡孔结构,同时分析了泡孔调节剂ACR用量对PVC木塑发泡复合材料中泡孔大小,泡孔结构及其在基体中分布状态的影响.结果表明:当木粉粒径为20目,AC与NaHCO3用量均为1份,ACR用量为8份时所得材料的综合性能最佳,泡孔结构最理想.     

Materials and testing for extrusion of RPVC construction products

Rigid PVC extruded construction products take many forms. Typical are house siding, window profiles, storm doors, pipe, fencing, and various accessory items generrally used for installation. In addition to these solid products, foam or cellular rigid PVC materials are entering the marketplace as substitutes for the traditional solid materials, or allowing PVC to capture other maintenance free applications; typical forms now in use include interior molding profiles and foam core pipe. This article focuses on the formulation ingredients constituting the articles mentioned above, how they are put together and influence the manufacturing process and final product, and how they can be tested to determine fit to the application requirements.     

Reduction of time-releasing ammonia from polymer foam using low acidic polymers

Polymer foams are used in everyday life for industrial and household applications. However, the time-releasing ammonia is environmentally harmful that becomes attractive. Here, we introduce a technically advanced synthetic process for the polyvinyl chloride (PVC) foam, in which the emission of ammonia gas is significantly reduced by using the polymeric acids. The PVC foam has processed with azodicarbonamide (ADCA) as a chemical blowing agent after the solid type polymeric acid is mixed as supporting agent. While the characteristic properties such as specific gravity (density) and chromaticity of PVC foams are not critically changed, the reduction of time-releasing ammonia is up to 85% compared to the PVC foam without polymeric acid. This is attributed to the cell structure with small sub-cells and lots of connecting channels and the chemically capturing ammonia of polymeric acids.     

PVC/WF发泡材料的性能研究

采用NaOH溶液、丙烯酸丁酯、甲基丙烯酸甲酯和硅烷偶联剂KH-550分别对木粉(WF)进行表面处理,利用傅立叶变换红外光谱仪对其进行表征,并用处理过的WF增强聚氯乙烯(PVC)树脂,经一步模压法制备PVC/WF发泡材料.对其进行力学性能、物理性能测试,比较不同表面处理方法对该发泡材料各项性能的影响.结果表明,WF经表面处理后制备的PVC/WF发泡材料性能均有所提高,其中以NaOH处理后所得复合材料综合性能最优:拉伸强度提高112%,密度从205.4 kg/m3减小到102.3 kg/m3,吸水率、吸油率和线性收缩率均有大幅度改善.     

CM与PVC共混发泡性能的研究

采用模压法进行发泡,研究了氯化聚乙烯(CM)与聚氯乙烯(PVC)的共混比和发泡剂用量对发泡体的泡体性能、泡孔结构的影响。结果表明,不同CM/PVC共混比的复合材料,随体系中CM的增加,发泡密度逐渐减小、泡孔体积和发泡倍率逐渐增大,当CM/PVC=50/50时,发泡材料具有较好的综合性能;改变共混体系中发泡剂AC的用量,测试泡体性能及观察泡孔结构得出,随AC发泡剂用量的增加,发泡材料的发泡密度减小,其相应的物理机械性能如拉伸强度、撕裂强度逐渐降低。     

The effects of plasticizers on the properties of poly(vinyl chloride) foams

The effects of plasticizers on poly(vinyl chloride) (PVC) plastisol mixtures were investigated. The investigations were carried out by determining the density of the PVC foam obtained by gelling the plastisol, as well as its elasticity and degree of expansion. Two series of experiments using different types of PVC were performed, using eight plasticizers, individually or as mixtures. Two-component plasticizer mixtures showed better properties than single-component plasticizers, and mixtures of di-iso-heptyl phthalate (DiHP) and butyl benzyl phthalate (BBP) proved to be the most appropriate. The effect of plasticizer amount also was investigated, and of the three parameters studied, the foam density, which steadily increased with plasticizer amount, was the critical one. It was also shown that in order to obtain consistent results, the foam expansion had to be precisely timed and the temperature carefully chosen.     

Continuous extrusion production of microcellular rigid PVC

This study examined the effect of Poly[vinyl chloride] (PVC) formulation on the cell morphology and density of rigid PVC foamed with supercritical CO₂ in a continuous extrusion process. Cell morphology and the density of foamed samples were controlled by blending two acrylic‐based processing aids (all‐acrylic foam modifier K‐400 and acrylic‐based impact modifier KM‐334), using a mixture design. The effect of blend ratios on the fusion and die swell behaviors of PVC was investigated by means of a torque rheometer and on a single‐screw extrusion capillary rheometer, respectively. Fusion was promoted as the relative amount of the all‐acrylic foam modifier increased in the blends. Similarly, the elastic constant of PVC, derived from the linear relationship between the die swell and apparent shear stress, increased upon increasing the relative amount of the all‐acrylic foam modifier in the blends, thus suggesting an increase in the melt elasticity of PVC. Microcellular rigid PVC foams with densities of approximately 0.15 g/cm³ and a tenfold volume expansion were produced. An optimum ratio of impact modifier to all‐acrylic foam modifier of 1:3 was found to maximize the foam expansion. Using impact modifier alone or all‐acrylic foam modifier alone yielded expansions considerably lower than that achieved with the 1:3 blend. The experimental results indicated that fusion is not the only criterion to control the cell morphology and density achieved in microcellular rigid PVC foams. The melt must have a viscosity low enough to allow bubble formation and growth, as well as elasticity high enough to prevent cell coalescence. J. VINYL ADDIT. TECHNOL., 2009. © 2009 Society of Plastics Engineers     

一种硬质PVC用复合发泡剂的制备及热性能研究

用碳酸氢钠（NaHCO3）、偶氮二甲酰胺（AC）及硬脂酸铅（PbSt）为原料制备吸放热复合发泡剂,通过差热与热重分析研究了发泡剂的热分解性能。结果表明：NaHCO3与AC之质量比为100∶20的发泡剂分解温度在170～188℃之间,且分解平稳,适合硬质PVC发泡材料加工。PbSt含量超过10%会影响发泡剂的分解率。用自制的吸-放热复合发泡剂用于硬质PVC挤出制备发泡材料,其密度可达约0.8g/cm3,且发泡材料泡孔细密均匀。     

低密度交联硬质聚氯乙烯泡沫塑料的研究

以酸酐和异氰酸酯为交联组分,糊用聚氯乙烯为基体树脂,制备了低密度交联硬质聚氯乙烯(Crosslinked-PVC)泡沫塑料。考察了甲基六氢苯酐、偏苯三酸酐和对苯二甲酸与甲苯二异氰酸酯及多亚甲基多苯基多异氰酸酯的不同官能度配比对模压块和泡沫塑料交联度的影响,酸酐/异氰酸酯配比对泡沫塑料的性能影响,不同[K]值PVC树脂对泡沫塑料的性能影响。研究表明,异氰酸酯和酸酐的官能度对模压块和泡沫塑料的交联度影响十分显著,模压块中过早产生交联对后续发泡过程不利。随着酸酐/异氰酸酯摩尔比的增加,泡沫密度减小,压缩强度降低,且泡沫密度达到最低密度的时间缩短。当糊用PVC树脂[K]值过小时,发泡体系容易发生并泡和中间鼓泡;当[K]值过大时,压缩性能反而下降。制备的Crosslinked-PVC泡沫塑料具有半互穿聚合物网络结构。     

改性剂和增塑剂对PVC微孔泡沫塑料形态影响

以超临界CO2为发泡剂,用自制的动态模拟发泡装置研究了聚氯乙烯(PVC)配方中改性剂丙烯酸酯类高分子聚合物(ACR)含量和增塑剂邻苯二甲酸二辛酯(DOP)含量对PVC微孔塑料泡孔形态的影响.结果表明,在其他工艺条件和配方相同的情况下,ACR为4份时得到的PVC微孔泡沫塑料泡孔密度最大,泡孔粒径最小,DOP为2～6份时比较适合PVC微孔发泡,并且振动力场的引入有利于得到细小均匀的微孔结构.     

Vinyl foam: A viable substitute for wood

Rigid vinyl foam offers fabricators a maintenance-free alternative to wood. It is suitable for both internal and external uses, and unlike wood, vinyl foam products will not rot, warp, or peel, and will never need painting. In order to thoroughly evaluate potential applications for foam PVC, samples were provided to a commercial cabinet manufacturer to obtain his perspective of pertinent properties and potential applications. Results of this evaluation are presented along with processing and formulation recommendations for making good-quality PVC foam.