木粉表面处理对PVC／木粉复合材料性能的影响

使用钛酸酯偶联剂、油酸酰胺、聚氨酯预聚物三种表面改性剂处理木粉并制备了PVC／木粉复合材料，研究了表面改性剂的不同种类和不同用量对复合体系性能和结构的影响。结果表明：几种木粉表面处理剂均可明显提高复合材料的力学性能，其中使用4份聚氨酯预聚体和6份油酸酰胺处理木粉表面的复合体系的力学性能较优；使用表面改性剂处理木粉，也可以明显改善复合体系的流变性能；同时扫描电镜观察也发现同样规律，体系中添加改性剂，PVC与木粉的相容性明显改善，材料性能也有所提高，但表面改性剂用量过多，也会造成木粉团聚，从而影响复合材料的性能。     

CPE对发泡PVC/木粉复合材料熔体流变性能的影响

采用旋转流变仪,应用小振幅流变测试法研究了抗冲击改性剂氯化聚乙烯（CPE）对发泡聚氯乙烯(PVC)/木粉复合材料熔体流变性能的影响。实验结果表明：角频率（ω）在0.1～100 rad/s之间时,随ω的增大,发泡PVC/木粉复合材料熔体的复数黏度（η*）降低,表现出"剪切变稀"效应,熔体的储能模量（G′）和损耗模量（G〞）随ω的增大而增加;加入5份CPE时,复合材料熔体的G〞明显提高,G′变化幅度较小,熔体的η*增加,促进了PVC的凝胶化;继续增加CPE的用量到10份,发泡PVC/木粉复合材料熔体的G〞和G′降低,η*也降低;随着ω的增加,加入CPE使样品的损耗角正切明显降低,熔体的弹性响应增加。加入10份CPE时,发泡PVC/木粉复合材料的冲击强度提高20 ％。     

微发泡硬质PVC/木粉体系型材的挤出

以植物纤维机制木粉取代通常的矿物填料，成功地制得了微发泡硬质PVC／木质体系的塑料型材，分析和讨论了型材的结构特点、工艺要点以及聚合物和木粉的界面改性。     

ACR对硬质PVC流变性能的影响

研究了丙烯酸酯类加工助剂(ACR)的种类和用量对硬质聚氯乙烯(RPVC)流变温度和塑化时间的影响;并分析了ACR的种类和用量与RPVC流变时效、凝胶速度和流变扭矩的关系。结果表明：ACR的种类和用量对TB、TG的影响不大,而对Tx有影响,且能够加快TB、TG的到来;当PA21与K125P用量为1phr时,能延长Tx的到来,但随着用量增加,迅速加快Tx的到来。ACR能促进RPVC的塑化,并使塑化时间tA-X随着用量的增加而缩短。ACR的加入,提高了RPVC的凝胶速度。ACR的用量对流变扭矩的影响主要在塑化初期,并随着塑化进程的发展而逐渐弱化。在相同用量下,PA21与K125P的q值非常接近,但比ACR401大,说明PA-21与K125P的粘附力相当,且都比ACR401大。     

异氰酸酯处理木粉对PVC/木粉性能的影响

采用木粉填充聚氯乙烯(PVC)基木塑复合材料,研究异氰酸酯处理木粉对PVC/木粉性能的影响.红外光谱、DMA和sEM较好地证明异氰酸酯和木粉之间的作用,结果表明:用异氰酸酯处理的木粉填充PVC,能够改善木粉与PVC之间的界面粘结作用,提高PVC/木塑复合材料的力学性能.     

PVC/木粉复合材料的性能研究

采用聚氯乙烯树脂和木粉制得PVC／木粉复合材料。研究了木粉的粒径、用量,表面处理剂的类型、用量DOP以及抗冲改性剂CPE的用量对复合材料的力学性能的影响。结果表明：当木粉的粒径为过20目筛、用量为30％表面处理剂为木粉用量的1．5％,DOP和CPE的用量为PVC的用量的10％时,所得的复合材料的综合性能最佳。     

无机阻燃剂对PVC/木粉复合材料性能的影响

分别采用A1(OH)3、ZB以及Sb2O3等无机阻燃剂对PVC/木粉复合材料改性,研究不同的阻燃剂配方及阻燃剂含量对PVC/木粉复合材料阻燃性能和力学性能的影响。结果表明:随着A1(OH)3,ZB以及Sb2O3添加量的增加,PVC/木粉复合材料的氧指数(LOI)呈逐渐增大的趋势。Sb2O3阻燃效率最高,当添加量为9份时,氧指数达到35.2%;无机阻燃剂的加入普遍降低了PVC/木粉复合材料的冲击韧性,但对拉伸强度起到了一定的增强作用。     

PVC/木粉复合材料的发泡研究

采用PVC树脂和木粉加入发泡剂制得PVC/木粉发泡复合材料。通过差示量热扫描分析(DSC)考察了偶氮二甲酰胺(AC)、NaHCO3及AC/NaHCO3/PVC稳定剂共混物的热分解特性。研究了木粉的不同粒径、AC发泡剂、NaHCO3、交联剂DCP和ACR的含量对复合材料力学性能的影响。结果表明:通过发泡能有效降低材料的密度;当AC含量为PVC用量的1%,木粉粒径为20目,NaHCO3与AC用量比为1∶1,DCP含量为PVC用量的0.4%,ACR含量为PVC用量的8%,所得的发泡复合材料综合性能较好。     

BoltornTM型超支化聚酯对硬质PVC流变性能的影响

采用HAKKE转矩流变仪,分析并讨论了超支化聚酯BoltornTM的用量和代数以及加工条件对硬质PVC流变性能的影响。结果表明,随着BoltornTMH30用量的增加,PVC塑化时间减少。不同代数的超支化聚酯对PVC的塑化效果不同,BoltornTMH30对PVC的塑化效果最好,塑化时间最短。该超支化聚酯/PVC共混物的最佳加工温度为175℃左右,最佳转速为50~60r/min。     

高密度聚乙烯／木粉复合材料熔融性能及表面张力的研究

探讨了木粉及马来酸酐接枝聚乙烯(MAPE)对高密度聚乙烯(HDPE)/木粉复合材料熔融性能及表面张力的影响。结果表明:复合材料的起始熔融温度均略高于纯HDPE的,熔融峰的面积及形状介于纯木粉与纯HDPE之间,复合材料的表面张力及其极性组分均随木粉的质量分数逐渐增加。使用MAPE将提高复合材料熔融峰的面积,复合材料更难被熔化。质量分数为5%、10%的MAPE的复合材料的表面张力较低;而质量分数为15%及20%的MAPE的复合材料的表面张力与无MAPE的复合材料的基本相等。     

Fusion characteristics of rigid PVC/wood‐flour composites by torque rheometry

This study was aimed at examining the effects of wood flour contents, wood species (softwood vs. hardwood), and particle size on the fusion characteristics (fusion time, fusion temperature, fusion torque, and fusion energy) of rigid PVC/wood‐flour composites in a torque rheometer. Neat rigid PVC exhibited one fusion peak, whereas the addition of wood flour into the PVC matrix led to two fusion peaks. Increased wood flour content caused a significant increase in the time, temperature, and energy at which fusion between the primary particles started, thereby leading to increased fusion torque, irrespective of the wood flour species. These results implied that rigid PVC filled with wood flour must be processed at higher temperatures than neat resin. Although fusion characteristics of the composites were influenced by the wood species, a clear trend between softwood and hardwood species could not be established. However, finer particles fused more quickly and needed less energy than coarse ones. J. VINYL ADDIT. TECHNOL., 13:7–13, 2007. © 2007 Society of Plastics Engineers.     

Synergistic effect of talc/calcined kaolin binary fillers on rigid PVC: Improved properties of PVC composites

This study aims to develop poly(vinyl chloride) (PVC) composites prepared by melt mixing by using a combination of talc and calcined kaolin as filler in order to improve the disadvantages of rigid PVC, which is widely used in industry, such as poor mechanical properties and low thermal stability. In addition, PVC/talc and PVC/calcined kaolin composites were also examined for comparison. The calcined kaolin is modified with urea to increase the surface area (chemical treatment), while the surface of both fillers is coated with stearic acid for good compatibility with PVC (mechanical treatment). Scanning electron microscopy micrographs showed homogeneous distribution of mechanically processed fillers. Attenuated total reflectance–Fourier-transform infrared spectroscopy analysis revealed successful coating of the fillers with stearic acid. Also, new bands were detected in the spectrum of urea-treated calcined kaolin, showing an effective chemical treatment. It has been observed that the treatment of fillers improves the mechanical properties of PVC. Thermogravimetric results showed that delaminated calcined kaolin increased the thermal stability of PVC composites. The results of this study proved that binary filler composites combine good properties of both (synergistic effect) and good filler dispersion can be obtained by using stearic acid and urea.     

Wood/plastic composites co‐extruded with multi‐walled carbon nanotube‐filled rigid poly(vinyl chloride) cap layer

Wood/plastic composites (WPCs) can absorb moisture in a humid environment due to the hydrophilic nature of the wood in the composites, making products susceptible to microbial growth and loss of mechanical properties. Co‐extruding a poly(vinyl chloride) (PVC)‐rich cap layer on a WPC significantly reduces the moisture uptake rate, increases the flexural strength but, most importantly, decreases the flexural modulus compared to uncapped WPCs. A two‐level factorial design was used to develop regression models evaluating the statistical effects of material compositions and a processing condition on the flexural properties of co‐extruded rigid PVC/wood flour composites with the ultimate goal of producing co‐extruded composites with better flexural properties than uncapped WPCs. Material composition variables included wood flour content in the core layer and carbon nanotube (CNT) content in the cap layer of the co‐extruded composites, with the processing temperature profile for the core layer as the only processing condition variable. Fusion tests were carried out to understand the effects of the material compositions and processing condition on the flexural properties. Regression models indicated all main effects and two powerful interaction effects (processing temperature/wood flour content and wood flour content/CNT content interactions) as statistically significant. Factors leading to a fast fusion of the PVC/wood flour composites in the core layer, i.e. low wood flour content and high processing temperature, were effective material composition and processing condition parameters for improving the flexural properties of co‐extruded composites. Reinforcing the cap layer with CNTs also produced a significant improvement in the flexural properties of the co‐extruded composites, insensitive to the core layer composition and the processing temperature condition. Copyright © 2009 Society of Chemical Industry     

Photoaging and stabilization of rigid PVC/wood‐fiber composites

Ultraviolet (UV) weathering performance of unpigmented and rutile titanium dioxide pigmented rigid polyvinyl chloride (PVC)/wood‐fiber composites has been studied. The composite samples were manufactured by dry‐blending PVC, wood fibers, and other processing additives in a high‐intensity mixer. The dry‐blended compounds were extruded and compression molded into panel samples. The manufactured samples were artificially weathered using laboratory accelerated UV tests. Composite samples were exposed to 340‐nm fluorescent UV lamps and assessed every 200 h, for a total of 1200 h of accelerated weathering. Each assessment consisted of a visual examination of surface roughness or erosion, a contact angle measurement, a FTIR collection, and a color measurement. The experimental results indicated that wood fibers are effective sensitizers and that their incorporation into a rigid PVC matrix has a deleterious effect on the ability of the matrix to resist degradation caused ultraviolet irradiation. The light stability of these composites could be improved quite efficiently with the addition of rutile titanium dioxide photoactive pigment during formulation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1943–1950, 2001     

转矩流变仪在测定PVC树脂塑化性能方面的应用

介绍了运用附带数据处理机的流变仪PL2000-6分析通用PVC树脂的流变行为,通过“相关程序”研究了国内外同牌号PVC树脂的熔融曲线,发现国产PVC树脂和进口产品在塑化性能方面存在着一定的差距。     

Effect of the addition of wood flours on the properties of rigid polyurethane foam

The objective of this study is to investigate an appropriate process to fabricate the wood‐polyurethane hybrid composites [wood‐polyurethane foam (PUF)]. Rigid PUFs that contain up to 20% wood flours were successfully fabricated from polymeric 4,4‐diphenylmethane diisocyanate, polyols, silicone surfactant, dibutin dilaurate/dimethylethanolamine catalysts, and distilled water (chemical blowing agent). The effects of hydroxyl value of polyols, wood flour particle size, wood flour content, isocyanate index, and water amount on the compressive property of foam were investigated. The morphology of the cell was observed with a scanning electron microscope. Wood‐PUF with different densities were prepared at different water contents in the wood flours. The relationship between the compressive property and density was established following the Power law. The incorporation of wood flour improved the compressive property of PUF, whereas its tensile and flexural properties were reduced. The thermal stability of the PUF was improved with the addition of wood flour. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

浅谈PVC物料的流变特征

通过分析PVC高聚物的流变性能,讨论了PVC物料在挤出机中和转矩流变仪中的流变特征,阐述了两种流变特征的相互关系及应用。     

钙/锌稳定剂对硬质PVC制品耐候性能的影响

介绍了影响PVC硬制品耐候性能的因素,研究了钙/锌稳定剂对PVC硬制品耐候性能的影响。     

PVC/木塑复合材料挤出发泡的研究进展

由于木塑复合材料的独特优点,使其需求迅速增长,很多国家正着手建立本国的木塑工业体系。总结了国内外在PVC木/塑复合材料挤出发泡研究上取得的进展,分别从木粉处理、配方、成型工艺及成型设备等关键技术上介绍PVC木/塑发泡复合材料研究取得的成就。并就当前的发展情况,提出了PVC木/塑发泡材料的发展方向。