PVA增塑性能正交试验研究

利用正交试验设计增塑剂与聚乙烯醇(PVA)共混配方,并进行熔融共混模压成型制备增塑PVA薄膜,通过对薄膜的力学性能、熔点、耐水性等性能进行测试,运用正交试验法研究复配增塑剂配方中蒸馏水、甘油、己内酰胺和二甲基亚砜的用量对薄膜拉伸强度、熔点和吸水率的影响。结果表明:增塑改性PVA的复配增塑配方中己内酰胺对拉伸强度影响程度最大,蒸馏水对熔点和吸水率的影响较大。较优的改性PVA复配增塑剂配方为:蒸馏水10 g,甘油10 g,己内酰胺20 g,二甲基亚砜8 g。     

长链乙烯酯改性聚乙烯醇热塑加工性能的研究

通过山梨醇和甘油复配增塑改善长链乙烯酯改性聚乙烯醇(PVA)的热塑加工性能,采用差示扫描量热仪、高压毛细管流变仪、万能试验机等研究了复配增塑剂与改性PVA的相互作用及其对改性PVA热性能、流变性能、力学性能、溶胀性能等的影响。结果表明,山梨醇和甘油复配增塑剂中的羟基可与改性PVA分子链中的羟基形成氢键,减小了PVA分子链间氢键相互作用,使体系黏度减小,分子链的活动性增强,降低了改性PVA熔点,改善了PVA熔体流动性,有利于实现PVA的热塑加工。复配增塑剂增加了PVA的自由体积,使PVA分子链的运动更加容易,提高了材料的柔韧性及断裂伸长率,减少PVA对水的吸收。当增塑剂含量为10%时,复配增塑剂不易析出,可同时改善改性PVA的流变性并使材料保持优异的力学性能。     

高熔点多元醇增塑聚乙烯醇的制备与性能

以高熔点多元醇季戊四醇(TMM)为主增塑剂、辅以相容剂和润滑剂形成复配增塑剂,对聚乙烯醇(PVA)进行增塑改性,以增大温度加工窗口,提高其热稳定性,实现改性PVA的熔融加工成型。采用差示扫描量热仪(DSC)、热重分析仪(TGA)、熔体指数仪测试了改性PVA的热性能和流动性能;采用扫描X射线衍射(XRD)、电子显微镜(SEM)对其结晶结构与形貌进行了测试与观察;然后进行了力学性能测试。结果表明,高熔点多元醇增塑剂用于增塑PVA,具备降低PVA的熔点,提高分解温度,增加流动性,使改性PVA具有良好的熔融加工性能,可用于注塑与挤出加工,制品具备良好的力学性能。     

复配增塑剂改性聚乙烯醇的热塑加工性能研究

以甘油/二缩三乙二醇(GP)为主增塑剂,N-甲基吡咯烷(NMP)辅助增塑剂,对聚乙烯醇(PVA)进行增塑改性,研究了增塑剂类别和配比对PVA的增塑效果。通过红外光谱分析(FTIR)研究了复配增塑剂与PVA间的相互作用,采用X射线衍射分析(XRD)、差示扫描量热分析(DSC)、热失重分析(TGA)表征了改性PVA的结晶性能和热性能,采用熔融指数仪和转矩流变仪研究了改性后PVA的热塑加工性能。结果表明:复配增塑剂能有效地破坏PVA自身的氢键,降低PVA的熔融温度和结晶度,改善PVA的热塑加工性能,并成功实现了改性PVA的注塑成型。通过注塑成型的PVA具有较好的力学性能,拉伸强度为28.6 MPa,断裂伸长率为534%。     

碳酸钙高填充聚乙烯醇复合材料热塑加工性能研究

采用分子复合和增塑,以水、多元醇和含酰胺基团化合物组成复配增塑剂,通过热塑加工制备了碳酸钙(CaCO3)高填充聚乙烯醇(PVA)复合材料,采用差示扫描量热仪(DSC)、热重分析(TG)、高压毛细管流变仪等研究了复合材料的热性能、流变性能,探讨了复合材料中增塑剂的迁移率及其对制品尺寸稳定性的影响。结果表明,通过分子复合和增塑后,改性PVA及PVA/CaCO3复合材料获得较宽热塑加工窗口,当CaCO3含量为70%时热塑加工窗口达85.5℃;PVA/CaCO3复合材料的熔体为假塑性流体,其黏度满足传统挤出或注塑加工的黏度需要;随环境湿度增加,复合材料中增塑剂迁移率增加,CaCO3可抑制复合材料中增塑剂的迁移,一定程度上提高了复合材料的尺寸稳定性。     

聚乳酸增塑体系熔体流动性及力学性能研究

通过熔融共混法,分别以乙酰柠檬酸三丁酯(ATBC)、己二酸二丁基二甘酯(增塑剂A)、异山梨醇硬脂酸酯(增塑剂B)、癸二酸二丁酯(DBS)为增塑剂,以丙烯酸型抗冲改性剂为增韧剂,制备了增塑聚乳酸(PLA)和复配增塑增韧PLA,研究了复配改性PLA的熔体流动性和力学性能,考察了增韧剂对PLA增塑体系的影响。结果表明:增塑剂A增塑PLA的综合性能较好;增韧剂可有效降低材料的熔体流动速率,提高材料的缺口冲击强度和断裂伸长率,但其拉伸强度有所降低。     

聚乙烯醇吹膜加工性能研究

研究了聚乙烯醇(PVA)吹膜加工性能。经两种不同的增塑剂复配增塑后，可明显改善其加工流动性，当复合增塑剂用量为25phr以上，PVA可以被较好地增塑，熔融塑化温度趋于定值。热性能研究表明，PVA为不完全结晶，其熔融曲线呈不规则分布。从PVA的流变性能可知，PVA熔体呈非牛顿性流体，剪切粘度随剪切速率增加而下降，并且醇解度较高的树脂，剪切粘度也较高。不同醇解度的PVA树脂，均能通过增塑改性后熔融挤出加工吹塑成膜。高醇解度PVA膜的水溶解温度高，而低醇解度PVA膜具有低温快速水解的性能。     

己内酰胺增塑亚麻/大豆蛋白复合材料的性能测试

通过对己内酰胺增塑过亚麻大豆蛋白复合材料性能测试表明：增塑剂的加入对复合材料吸水率和断裂伸长率的影响比较显著,加入增塑剂己内酰胺后,复合材料吸水率大幅下降,断裂伸长率和熔体流动性有了显著改善,其拉伸强度略有下降。     

热塑性木薯淀粉/聚乙烯醇复合材料的制备、结构与性能研究

采用熔融法制备热塑性木薯淀粉(TPS)/聚乙烯醇(PVA)复合材料,研究PVA和增塑剂的种类、用量对TPS/PVA复合材料的加工、力学性能、回生行为及结构影响。研究结果发现随着PVA用量的增加,TPS/PVA复合材料的塑化时间缩短、塑化扭矩和平衡扭矩增大;随着甘油增塑剂用量的增加,TPS/PVA复合材料的塑化时间、扭矩降低。TPS/PVA-1788复合材料的塑化时间、塑化扭矩和平衡扭矩均比TPS/PVA-1799复合材料的小;采用尿素/甲酰胺复配增塑TPS/PVA复合材料的塑化时间、塑化扭矩和平衡扭矩比使用甘油小。随着PVA用量的增加,TPS/PVA复合材料的拉伸强度增加;TPS/PVA-1799复合材料的拉伸强度比TPS/PVA-1788复合材料的高。使用甘油增塑TPS/PVA复合材料的拉伸强度高于使用尿素/甲酰胺复配增塑剂。随着回生时间增加,TPS/PVA复合材料的回生焓增加。添加PVA加速TPS的回生过程,随着PVA用量进一步增加,TPS/PVA复合材料回生降低。PVA能削弱TPS的氢键作用,提高TPS塑化程度,有利于TPS/PVA复合材料的均匀性。     

聚乙烯醇的共混改性

将两种牌号聚乙烯醇(PVA)(PVA1799和PVA0599)混合,然后分别加入甘油/三甘醇、甘油/乙酰胺复合增塑剂对其进行改性。加入复合增塑剂使PVA1799/PVA0599的熔点、结晶度和热分解温度降低;与PVA1799/PVA0599体系相比,改性PVA1799/PVA0599的拉伸强度下降、拉伸断裂应变明显提高;随着PVA0599含量增加,改性PVA1799/PVA0599的熔体流动速率增大;m(PVA1799)/m(PVA0599)为3∶2时,随复合增塑剂用量增加,改性PVA1799/PVA0599的流动性变好;甘油/乙酰胺增塑效果优于甘油/三甘醇;改性PVA1799/PVA0599体系在复合增塑剂为30 phr时可望实现熔融加工。     

Evaporation behaviour of water and its plasticizing effect in modified poly(vinyl alcohol) systems

Several modified poly(vinyl alcohol) (PVA) systems with various plasticizers were prepared and their melt‐processing was successfully realized. This paper focuses on the study of the evaporation behaviour of water in these modified PVA systems, exploring its plasticizing mechanism by using differential scanning calorimetry. The evaporation characteristics of bulk water, water in aqueous solutions of the plasticizers, and the thermal properties of PVA were also studied. The experimental results show that water in aqueous solutions of glycerol and/or caprolactam evaporates at a lower temperature than bulk water, but water in the PVA/water system evaporates at a higher temperature, with a wider DSC peak due to the interaction between water and PVA. Incorporation of glycerol, caprolactam or their mixtures further strengthens the interactions between water and the other components, retarding water evaporation. During the processing, the less closely associated water has the plasticizing effect through molecule movement, while the strongly bound water, which breaks the intermolecular hydrogen bonding of PVA and decreases its intermolecular interaction, is more beneficial to the melt‐processing of PVA. Copyright © 2003 Society of Chemical Industry     

淀粉/三聚氰胺增塑PVA熔融加工膜的制备及性能

以淀粉/三聚氰胺为复配增塑剂,利用熔融加工工艺制备聚乙烯醇(PVA)膜,采用差示扫描量热(DSC)、热失重分析(TG)和力学性能测试等考察了增塑剂含量对PVA膜性能的影响.结果表明,复配增塑剂能有效破坏分子链间氢键,对PVA的增塑作用明显.随增塑剂含量增大,PVA膜的力学性能和熔体质量流动速率呈先增大后减小的趋势,熔点...     

Effects of Plasticizing on Mechanical and Viscous Characteristics of Poly(vinyl alcohol): A Comparative Study between Glycerol and Diethanolamine

Although plasticizing materials by modification with small-molecular chemicals has been extensively utilized in the industrial community, processing poly(vinyl alcohol) (PVA) at high concentrations (C_PVA) or with a high degree of polymerization (DP) remains challenging. Optimization the plasticizing conditions is one means of addressing this issue. In this study, two types of frequently used plasticizers, glycerol (GLY) and diethanolamine (DEA), are chosen to plasticize PVA resin with a DP of 2400. Both PVA/plasticizer films possess excellent optical transmittance and mechanical ductility, whereas the films blended with DEA exhibit higher strength than the PVA/GLY films. The viscosity variation in the temperature (T_op)–C_PVA space is monitored by real-time viscous flow testing, demonstrating that DEA is more effective for reducing the viscosity of PVA, which should improve the processability, facilitating film-forming from concentrated solutions. Furthermore, density functional theory calculations and molecular dynamics simulations illustrate that the PVA/DEA system has a lower binding energy, longer hydrogen bond length, and higher isotropic diffusion coefficient, indicating a stable hydrogen bond network and homogenous dispersion of the plasticizer, leading to good solution fluidity and mechanical performance. This study is significant for guiding the design and manufacture of optically transparent, high-performance PVA films as polarizer precursor.     

Melt processing of poly(vinyl alcohol) through adding magnesium chloride hexahydrate and ethylene glycol as a complex plasticizer

The melt processing of poly(vinyl alcohol) (PVA) was achieved using magnesium chloride hexahydrate (MgCl₂·6H₂O) and ethylene glycol as a complex plasticizer. The interaction between the complex plasticizer and PVA was studied by Fourier transform infrared spectroscopy (FT‐IR). The PVA films were characterized using X‐ray diffraction (XRD), differential scanning calorimetry, thermogravimetric analysis (TGA), scanning electron microscope, and dynamic thermomechanical analysis (DMA) techniques. The band shift of the observed peak around 3335 cm^?1 in the FT‐IR spectra indicates that the complex plasticizer MgCl₂·6H₂O and ethylene glycol could form strong interactions with PVA and thus interrupt the intermolecular and intramolecular hydrogen bonding in PVA. The XRD results show that the addition of the complex plasticizer would significantly destroy the crystallites of PVA and result to the decrease of the degree of crystallinity of PVA. The melting point was reduced from 229°C of pure PVA to around 170°C after the plasticization. The TGA studies show that with the complex plasticizer, the thermal stability of PVA is improved. PVA plasticized by 30 wt% MgCl₂·6H₂O and 10 wt% ethylene glycol shows the tensile strength of 33 MPa and the elongation at break of 362%. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

Synthesis of a bio-based plasticizer from vanillic acid and its effects on poly(vinyl chloride)

A new bio-based plasticizer, VA8-8, was prepared derived from vanillic acid, and its structure was verified by nuclear magnetic resonance. It was incorporated into poly(vinyl chloride) (PVC) to replace dioctyl phthalate (DOP), and its plasticizing performance was evaluated. The results indicated that VA8-8 shows good compatible with PVC resin, and has a excellent plasticizing effect for PVC. When DOP was partially or completely substituted with VA8-8, the T_g value PVC blends dropped from 34.6 to 24.3°C and the elongation at break increased from 196.4% to 301.9%, suggesting the enhanced plasticizing efficiency of plasticizer. The plasticizing mechanism was also simulated, and the interactions between VA8-8 and PVC molecules were discussed. The thermogravimetric analysis showed VA8-8 can more effectively improve the thermal stability of PVC than DOP. In addition, the migration resistance of VA8-8 was generally superior to that of DOP. Therefore, VA8-8 is a comparable to or better plasticizer than DOP, and it is a promising alternative plasticizer for PVC.     

淀粉/PVA生物降解材料的热塑性研究

将聚乙烯醇(PVA)、淀粉、增塑剂在Hakke流变仪中共混制备了热塑性淀粉/PvA材料,研究了2种PVA-PVA1799、PVA1788,2种淀粉-玉米淀粉、木薯淀粉的热塑性情况;比较了甘油、乙二醇、乙酰胺3种增塑剂的增塑效果.结果表明:采用合适的增塑剂与适当的PVA、淀粉组合可以使PVA/淀粉共混体系在高温下热塑成型...     

Greffages mecanochimiques sur le polychlorure de vinyle. I. Polyméarisations amorcéaes par le malaxage

The grafting of methyl methacrylate and of methacrylic esters on poly(vinyl chloride) by mechanicochemical synthesis can be performed in the Brabender Plastograph. These monomers possess sufficient intermolecular plasticizing power to bring the poly(vinyl chloride)-monomer system into the viscoelastic state required for the formation of free radicals by homolytic scission of polymeric chains. Nevertheless several other monomers (among them the styrene) have interstructural plasticizing ability and can be grafted by mechanicochemical synthesis by addition of an intermolecular plasticizer or a monomer of the first class (methyl methacrylate). Also, except for basic monomers, the monomers stabilize poly(Vinyl chloride) during the mastication, probably because they act as free-radical scavengers.     

A dynamic mechanical and thermal analysis of unplasticized and plasticized poly(vinyl alcohol)/methylcellulose blends

The miscibility of poly(vinyl alcohol) (PVA)/methylcellulose (MC) blends was investigated over the entire composition range using the dynamic mechanical analyzer (DMA) and the differential scanning calorimeter (DSC). On the basis of the glass transition temperature, determined by DMA, one could conclude that the blends exhibited some miscibility below 80 wt % of MC and a good miscibility above 80 wt % of MC. The highest depressions of the melting and crystallization temperatures of the blends compared to those of PVA, determined via DSC analysis, were observed for MC contents greater than 80 wt %. The miscibility between PVA and MC can be attributed to the hydrogen bonds formed between the two components. The DMA studies showed that water is a good plasticizer for PVA and poly(ethylene glycol) 400 (PEG 400), a good plasticizer for MC. The inclusion of both water and PEG 400 in the blends revealed a synergistic plasticizing effect, which resulted in an increased miscibility between PVA and MC over a greater range of MC compositions (>60 wt %). The elongations of PVA, MC, and their blends were found to increase with the addition of PEG 400, but the tensile strengths to decrease. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1825–1834, 2001     

改性PVA热塑加工性能研究

采用熔体流动速率试验机研究了以水、甘油、聚乙二醇和己内酰胺为主的四种加工改性剂对聚乙烯醇(PVA)热塑加工性能的影响。采用平板硫化机压膜观察不同改性PVA体系的成膜性能。结果表明,加工改性剂在不同程度上改善了PVA的热塑加工性能,其中己内酰胺改性PVA体系具有最好的热塑加工性能;通过热压成型可以将改性PVA制成透明性很好的薄膜;熔体流动速率试验机可以有效地判断PVA改性体系的热塑加工性能。     

增塑剂对氯化聚乙烯防水卷材增塑效果的研究

分析了几种增塑剂[邻苯二甲酸二丁酯(DBP)、邻苯二甲酸二辛酯(DOP)、邻苯二甲酸二异癸酯(DIDP)、癸二酸二辛酯(DOS)、偏苯三甲酸三辛酯(TOTM)以及氯化石蜡等]对氯化聚乙烯(CPE)防水卷材的增塑机理。在保持其他条件不变的前提下,选取增塑剂的份数为25份,并在此基础上从力学性能、耐温性能、流变性能以及微观结构四个方面比较各种增塑剂与CPE树脂的相容性,从而比较它们的增塑效果。结果表明:DSC以及电镜结果显示邻苯类增塑剂效果明显优于其他类型增塑剂;其中DOP为主增塑剂的体系综合性能最好;DOS作为主增塑剂时具有良好的耐低温析出性;DIDP作为主增塑剂时具有耐高温析出性;氯化石蜡可作为辅助增塑剂;以上增塑剂可根据各自特点复配使用。