Perfluoropolyether-based organic-inorganic hybrid coatings

Perfluoropolyether-based organic-inorganic hybrids were prepared by sol-gel process and applied as functional coatings onto glass substrates. Contact angle analysis and X-ray photoemission spectroscopy were carried out in order to characterize the surface of the prepared coatings. A strong hydrophobic and lipophobic character was observed for all tested compositions. The wettability behaviour was found to be dependent on both the coating technique and the reaction time of the sol-gel reaction. A strong surface segregation of perfluoropolyether segments was noted for all the prepared samples as evidenced by XPS analysis. On the basis of the obtained results, these materials could be used as functional coatings to prepare water and oil repellent glasses or other substrates.     

Polyhedral oligomeric silsesquioxane as a novel plasticizer for poly(vinyl chloride)

This study focuses on investigating the use of polyhedral oligomeric silsesquioxanes (POSS) to plasticize poly(vinyl chloride) (PVC). Conventional organic plasticizers for PVC, such as dioctyl phthalate (DOP), are somewhat volatile, leading to plasticizer loss and unwanted deterioration of the material properties over time. Previous experimental results indicate that methacryl-POSS, which is much less volatile due to its hybrid organic-inorganic structure, has the ability to plasticize PVC. Methacryl-POSS is miscible in the PVC only up to 15 wt%, thereby limiting its suitability as a plasticizer. However, through the use of ternary compositions it is possible to increase the proportion of methacryl-POSS in PVC substantially. The T_g of appropriately formulated ternary PVC/POSS/DOP compounds can be reduced to near room temperature, and these materials exhibit desirable ductile behavior. Binary (PVC/DOP) and ternary (PVC/POSS/DOP) compounds formulated to the same T_g values showed considerably different mechanical properties. Such findings reveal the possibility of using POSS to engineer the mechanical properties of plasticized PVC.     

软聚氯乙烯塑料的气味分析研究

采用气相色谱-质谱法(GC-MS)对3种软聚氯乙(烯S-PVC)试样的挥发性有机物进行了测试,分析了产生气味的物质。结果表明:试样产生的挥发性有机物为烃类化合物、醇和醛、酯等羰基化合物,产生气味的化合物主要是羰基化合物;添加抗氧剂可阻止增塑剂和其他烃类的氧化,减少S-PVC塑料气味的产生。     

PVC／PS共混体系的改性研究进展

概述了聚氯乙烯和聚苯乙烯的共混改性研究的最新进展,迄今主要在是该体系中加入增容剂进行改性。希望增容,交联协同技术用于该本系的共混改性。     

The role of plasticizer on the exfoliation and dispersion and fracture behavior of clay particles in PVC matrix: a comprehensive morphological study

The clay nanoparticles are readily dispersed and exfoliated in the PVC matrix with the help of Dioctyl phthalate (DOP) plasticizer. X-ray, TEM and AFM analysis of the nanocomposites indicate that there is an optimum concentration of DOP for the process. If used in high concentrations, the ability to transfer forces to the clay particles through the polymer matrix decreases due to substantial decrease in viscosity. The individual platy montmorillonite particles dispersed in PVC matrix were directly observed by AFM and found to lie preferentially on their basal surfaces, especially when the compounded batch is compression molded. The edges of the particles were in some cases straight forming hexagonal angles and in other cases irregular.     

Effect of plasticizer concentration and annealing on the structure of PVC

Samples of poly(vinylchloride) with various amounts of di-2-ethylhexyl phthalate plasticizer have been prepared by casting from solution. The enthalpy of fusion of these samples has been measured using differential scanning calorimetry. The results presented show the dependence of the enthalpy of fusion on plasticizer concentration, annealing time and annealing temperature to which the samples were subjected. The results indicated that the addition of plasticizer has surprisingly little effect on the crystallinity of commercial PVC. Small angle X-ray scattering measurements have also been carried out on samples of PVC plasticized with two different plasticizers. There was considerable similarity found between the two samples. Therefore SAXS results cannot be taken on the whole as a measure of crystallinity in this material.     

Fourier transform infrared spectroscopy in the study of the interaction between PVC and plasticizers: PVC/plasticizer compatibility

The interactions between Poly(vinyl chloride) (PVC) and Plasticizers, responsible for polymer plasticization, can be detected by means of Fourier transform infrared spectroscopy (FTIR). The interaction capacity between the two components depends on plasticizer chemical nature, PVC stereoregularity, and plasticizer content. In the case of ternary systems, consisting in PVC and two different plasticizers, their interaction with PVC depends essentially on their chemical nature. In this work, FTIR spectroscopy is applied to determine the effect of the cited factors on the compatibility between plasticizer and resin. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

氯化聚丙烯对PP/PVC共混物性能的影响

以氯化聚丙烯(CPP)为增容剂,探讨了CPP不同含量下PP/PVC体系的力学性能、相容性、流变性能以及对应的微观结构,并与氯化聚乙烯(CPE)增容剂进行了比较。发现添加5份CPP可明显改善PP和PVC两相界面相容性,与PP/PVC体系相比,拉伸强度提高了61%,无缺口冲击强度提高了100%。此时CPP还起到了一定的增塑作用,共混体系加工性能较好。与CPE相比,含有CPP的共混体系拉伸强度较高。     

PVC／共聚尼龙合金的性能研究

采用了乙烯－丙烯酸酯－一氧化碳共聚物（Ｆｌｖａｌｏｙ）及乙烯－丙烯酸酯－一氧化碳共聚物接枝马来酸酐（Ｆｕｓａｂｏｎｄ）两种增容剂对聚氯乙烯与二元共聚尼龙的共混物进行增容,得到了一类新型的ＰＶＣ／尼龙合金,并研究了合铆钉与比及增容剂对性能的影响。     

Recycling of PVC

Recycling of used PVC needs a careful characterization of PVC waste. The analysis of the scrap, especially with respect to the thermal stability and the molecular weight, is useful before reprocessing. Additional stabilization of used PVC can be done by up to 10 wt% fillers, e.g. chalk, which does not change the mechanical properties. A literature survey on the proposed concepts and methods for material and chemical recycling of PVC is given.     

The effects of thermomechanical history and strain rate on antiplasticization of PVC

Antiplasticization is mechanically characterized by an increase in the polymer stiffness and/or yield strength upon the incorporation of a small amount of a low-molecular weight diluent. It is attributed to hindrance of the local β-relaxation motions of the polymer. Here, we have studied the effects of thermal treatment, plastic deformation, and strain rate on the antiplasticization of the yield stress of a 95 wt% poly(vinyl chloride)/5 wt% dioctyl phthalate (PVC/5 wt% DOP) compound. Two thermal treatments were applied to the materials - cooling to room temperature from above T_g by a quench or by a slow oven-cool anneal. When compressed at low to moderate strain rates, antiplasticization was observed in the annealed (physically aged) PVC/5 wt% DOP but not in the quenched (unaged) PVC/5 wt% DOP. Load-unload-reload compression cycles revealed that antiplasticization can be erased by plastic strain; the anomalously high yield stress of PVC/5 wt% DOP observed in the first load cycle softens to a value lower than that of the neat PVC in subsequent cycles. The results indicate that disordered, high free volume microstructural states, obtained either from thermal quenching or from plastic straining, liberate the beta motions of the PVC molecule which, in turn, erase antiplasticization of the yield stress. Earlier work on the rate-dependence of yield has demonstrated that beta motions must be stress-activated in order to yield neat PVC when deformed at high strain rates (>100/s). Hence, we have characterized the rate-dependence of the antiplasticization of the yield stress by testing the annealed materials in uniaxial compression over a wide range of strain rates (10⁻⁴/s-3000/s). Antiplasticization was observed in PVC/5 wt% DOP in the low strain rate regime where beta motions are free in neat PVC but hindered in PVC/5 wt% DOP; however, the antiplasticization (elevation of yield stress) gradually diminished with increasing strain rate.     

Application of Poly(butylenes 2-methylsuccinate) as Migration Resistant Plasticizer for Poly(vinyl chloride)

The bio-based and biodegradable polyester poly(butylenes 2-methylsuccinate) (PBM) was successfully used as a polymeric plasticizer to modify poly(vinyl chloride) (PVC) in this work. The tensile properties, plasticization efficiency estimated by the lowered glass transition temperature and the enhanced elongation at break of the PVC/PBM blends and the migration stability of the PBM were investigated. It was indicated that the migration-resistant property of PVC plasticized with PBM was greatly superior to that with dioctyl phthalate (DOP). Furthermore, the tensile properties were comparable to that of PVC/DOP, indicating that the environmentally friendly PBM can be used as an alternative plasticizer to remove the potential health risks from migrating phthalates during applications.     

Rheological and mechanical properties of PVC/CaCO3 nanocomposites prepared by in situ polymerization

Poly(vinyl chloride) (PVC)/calcium carbonate (CaCO₃) nanocomposites were synthesized by in situ polymerization of vinyl chloride (VC) in the presence of CaCO₃ nanoparticles. Their thermal, rheological and mechanical properties were evaluated by dynamic mechanical analysis (DMA), thermogravimetry analysis (TGA), capillary rheometry, tensile and impact fracture tests. The results showed that CaCO₃ nanoparticles were uniformly distributed in the PVC matrix during in situ polymerization of VC with 5.0 wt% or less nanoparticles. The glass transition and thermal decomposition temperatures of PVC phase in PVC/CaCO₃ nanocomposites are shifted toward higher temperatures by the restriction of CaCO₃ nanoparticles on the segmental and long-range chain mobility of the PVC phase. The nanocomposites showed shear thinning and power law behaviors. The ‘ball bearing’ effect of the spherical nanoparticles decreased the apparent viscosity of the PVC/CaCO₃ nanocomposite melts, and the viscosity sensitivity on shear rate of the PVC/CaCO₃ nanocomposite is higher than that of pristine PVC. Moreover, CaCO₃ nanoparticles stiffen and toughen PVC simultaneously, and optimal properties were achieved at 5 wt% of CaCO₃ nanoparticles in Young's modulus, tensile yield strength, elongation at break and Charpy notched impact energy. Detailed examinations of micro-failure micromechanisms of impact and tensile specimens showed that the CaCO₃ nanoparticles acted as stress raisers leading to debonding/voiding and deformation of the matrix material around the nanoparticles. These mechanisms also lead to impact toughening of the nanocomposites.     

硅酸盐对软PVC阻燃性和热性能的影响

研究了硅酸盐对软聚氯乙烯(PVC)的阻燃作用。通过热分析法研究了经阻燃处理后软PVC从室温到800℃的热降解过程;通过剩炭率的测定,结合用扫描电子显微镜(SEM)对样品燃烧后剩炭结构的观察,探讨了硅酸盐的阻燃机理。结果表明:经硅酸盐处理的样品具有较高的氧指数(OI)和剩炭率,与未处理的样品相比具有较好的阻燃性能。硅酸盐的加入可改变PVC的热降解过程,使起始降解温度降低,最大失重速率加快,硅酸盐对软PVC的阻燃主要是由于凝聚相的Lewis酸催化作用以及高温下生成的玻璃体对剩炭的保护作用造成的。     

PVC片材表面的光接枝亲水化处理

采用光接枝聚合方法对商品化PVC片材进行了表面亲水化处理。以二苯甲酮作引发剂 ,丙烯酸为接枝单体研究了反应过程中单体浓度、引发剂浓度、反应时间对亲水化效果的影响。衰减全反射红外光谱 (ATR FTIR)分析发现 ,在 15 5 5cm-1处出现COO-的特征峰 ,证明丙烯酸已经接枝到材料表面。随着反应时间的延长 ,接触角持续下降 ,3 0s以后趋于恒定 ,最低可达 3 3°。较低单体浓度下 ,均聚反应较弱 ,材料的亲水性要好于高单体浓度时的情况。同样 ,较低引发剂浓度时 ,引发剂的自屏蔽效应弱 ,有利于接枝反应 ,接触角要比高引发剂浓度条件下小     

PA6含量对PVC/PA6共混物形态结构与力学性能的影响

以EVA-g-MAH为相容剂,将PVC与自制的低熔点PA6共混制备了PVC/PA6共混物。通过扫描电子显微镜(SEM)和力学性能测试研究了PA6含量对PVC/PA6共混物形态结构及力学性能的影响。SEM分析结果显示:随着PA6含量的增加,PVC/PA6共混物的分散相尺寸逐渐增大,当PA6含量为10%时,共混物中分散相的分散尺寸最小为1μm;当PA6含量为50%时,共混物为两相共连续结构;当PA6含量为60%时,共混物中PA6为连续相,PVC为分散相。力学性能测试结果表明:当PA6含量为10%时,共混物的缺口冲击强度和拉伸强度都较PVC有明显提高,分别提高了约50%与30%,达到了6.29kJ/m2和60MPa。采用差示扫描量热仪(DSC)研究了PVC/PA6共混物的结晶温度,检测结果显示:PVC/PA6共混物呈现非晶结构。     

氧化物的性能对PVC热稳定性的影响

通过对氧化物的粒度分布和比表面积的测定研究了氧化物表面性能对PVC热稳定性的影响。结果发现,氧化物的粒径大小对PVC动态热稳定性的影响具有决定性的影响,而氧化物的比表面积决定PVC静态热稳定性。     

Effect of liquid plasticizers on crystallization of PCL in soft PVC/PCL/plasticizer blends

In this work, poly(ε-caprolactone) (PCL) and liquid plasticizer were combined used to plasticize poly(vinyl chloride) (PVC), and the possibility of using PVC/PCL/plasticizer blends to fabricate soft PVC with enhanced migration resistance was investigated. Through partial replacement of liquid plasticizers in soft PVC by equal quantity of PCL, flexibility was maintained while extraction loss of plasticizer by organic solvent was reduced significantly. Furthermore, crystallization of PCL in PVC/PCL/plasticizer blends with low PCL content was observed, and crystallization rate of PCL was found to be influenced by plasticizer contents and structures. For instance, crystallization rate of PCL in PVC/PCL/diisononyl phthalate (DINP) (100/40/100) was 3.7 times faster than in PVC/PCL/DINP (100/40/80), while crystallization rate of PCL in PVC/PCL/dioctyl adipate(DOA)(100/40/100) was 8.3 times faster than in PVC/PCL/diisononyl cyclohexane-1,2-dicarboxylate (DINCH) (100/40/100). Low-field ¹H NMR test manifested that different crystallization rate of PCL in PVC/PCL/plasticizer blends with different plasticizer structures was triggered by difference in plasticizers' compatibility with PVC, that is, the number of interaction point between PVC and plasticizers. It is concluded that PCL crystallization favored by liquid plasticizers in PVC/PCL/plasticizer blends was induced by interaction competition between PVC/plasticizer and PVC/PCL. As plasticizer content increases or its compatibility with PVC decreases, interaction competition becomes more intense and consequently faster crystallization of PCL occurs. Thus, to obtain soft PVC products with improve migration resistance while avoiding PCL crystallization, the total content of plasticizer (including both liquid plasticizer and PCL) should be lower than 66 phr (40 wt %). © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48803.     

PVC/高分子表面修饰CaCO3复合材料的加工性能研究

采用液态高分子改性剂对CaCO3进行包覆改性,得到高分子表面修饰CaCO3(CLCC)。使用转矩流变仪、紫外可见分光光度计及白度测定仪对聚氯乙烯(PVC)/CaCO3复合材料和PVC/CLCC复合材料的加工性能进行了研究。结果表明,CLCC颗粒的加入可以缩短PVC的塑化时间,改善其加工性能,提高PVC生产效率;而抑制了PVC在熔融加工过程中的降解;PVC/CLCC复合材料的白度保持率高于PVC/CaCO3复合材料。