AN含量对PVC/SAN共混物相容性的影响

采用乳液聚合技术合成了一系列不同丙烯腈（AN）含量的苯乙烯-丙烯腈（SAN）共聚物,将其与聚氯乙烯（PVC）熔融共混,形成PVC/SAN共混物,并引入增塑剂邻苯二甲酸二辛酯（DOP）。通过动态力学分析仪（DMA）和扫描电子显微镜（SEM）对共混物的玻璃化转变温度和相结构进行表征,考察不同AN含量对PVC/SAN共混物相容性的影响。     

浅谈硬质PVC混料

针对硬质PVC混料的热混出料温度、混料顺序以及干混料的熟化时间等混料参数对干混料的加工行为的影响进行了探讨,同时对混料设备的选择、混料加料量及如何判断干混料的优劣做了简要的说明。     

Dynamic mechanical and morphological studies on the compatibility of plasticized PVC/thermoplastic polyurethane blends

In this work, the compatibility of blends of plasticized poly(vinyl chloride) (p‐PVC) and thermoplastic polyurethane (TPU) was investigated using a dynamic mechanical analyzer and scanning electron microscopy. Two kinds of TPU with different ratios of hard to soft segments, i.e., TPU90 and TPU70 were compared. p‐PVC/TPU90 and p‐PVC/TPU70 blends with variable weight ratios (100/0, 90/10, 80/20, 70/30, 60/40, 50/50, 0/100) were prepared by melt blending. PVC was plasticized with 40 phr of dioctyl phthalate. It was found that TPU with a lower hard segment (i.e., TPU70) is more compatible with plasticized PVC than TPU with a higher hard segment (i.e., TPU90) in over the composition ranges examined. It was concluded that the compatibility of plasticized PVC and TPU are dependent on the ratio of hard to soft segments in TPU. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 415–422, 1999     

Interactions between PVC and binary or ternary blends of plasticizers. Part I. PVC/plasticizer compatibility

Solid–gel transition temperatures, t_m, were measured for PVC in binary and ternary mixtures of plasticizers. Data were used to investigate interactions between plasticizers, and their effect on t_m and polymer–plasticizer interaction (χ) values. The UNIFAC-FV method was used to predict Gibbs free energy of mixing, and χ for a range of plasticizers, and interactions for one quaternary mixture. Synergy was observed when one or more branched phthalates were mixed with ODPP, but none when three phthalates were mixed. Mixtures of DOP with aliphatic ester plasticizers again produced synergy. Equations were produced to enable interaction coefficients of different plasticizer blends to be predicted. It was found that interaction coefficients increase as the difference in molar mass between the two plasticizers increases. Calculated χ values were generally similar to experimental values. The lower limit of Gibbs free energy of mixing required for plasticization of PVC using monomeric plasticizers was calculated to be about −0.9 J/g, and that for polymeric plasticizers −0.15 J/g. Equations were produced enabling Gibbs free energy of mixing to be predicted from the amount of C atoms in the plasticizer.     

聚乙烯/石蜡油共混体系动态流变行为和相容性

将分子量相差较大的两种聚乙烯(PE)分别与石蜡油(LP)组成共混体系,通过旋转流变仪、偏光显微镜(PLM)、差示扫描量热仪(DSC)和扫描电子显微镜(SEM)研究了温度和LP含量对共混体系动态流变行为的影响,并对两相共混体系的相容性及微孔结构进行了表征.结果表明,随着温度的升高和LP含量的增加,PE/LP共混体系的储能...     

Dynamic rheological behavior and mechanical properties of PVC/ACS blends

In order to increase the processability and mechanical properties of poly(vinyl chloride) (PVC), the terpolymer of acrylonitrile-chlorinated polyethylene-styrene (ACS) is used to modify the PVC. The plasticizing, rheological, and dynamic mechanical properties of PVC/ACS blends are investigated by means of torque rheometer, oscillation rheometer, and dynamic mechanical analyzer. The measurements of torque rheometer showed that both plasticizing time and stabilization torque are decreased with increasing ACS content. The PVC/ACS melts displayed larger dynamic storage modulus (G′), loss modulus (G′′), and complex viscosity (η*) than that of pure PVC, and these values reached maximum for the blend with 10 wt% ACS. When ACS content was below 10 wt%, PVC and ACS showed good compatibility in the blends by displaying a single T _g; however, when ACS content was more than 15 wt%, the phase separation phenomena occurred in the blends. PVC/ACS blends showed larger storage modulus (E′) and loss modulus (E′′) than that of pure PVC, but these values decreased with increasing ACS content. ACS can enhance both tensile and impact strength of PVC, and the impact strength reached maximum with 15 wt% ACS content which is higher 2.5 kJ/m² than the pure PVC. These results suggested that ACS is an efficient processing aid and toughening modifier for PVC at appropriate content.     

Evaluation of compatibility in SAN/EPDM blends by determination of the adhesion parameters

A series of various types (different structures) of ethylene-polypropylene-diene-graft-polystyrene (EPDM-g-PS) copolymers were synthesized and their surface property variations were studied using surface analysis techniques such as surface contact angle measurement. Pre-synthesized graft copolymers were added (5 phr) in styrene-acrylonitrile (SAN)/ethylene-propylene-diene (EPDM) blends composition of 95/5 and 90/10. The adhesion parameters at the interface, that is work of adhesion, the interfacial energy and the coefficient of wetting were calculated and correlated to the differential scanning measurements measurements and SEM micrographs in order to study the effect of graft copolymers on compatibility of SAN/EPDM blends. It is obvious that depending of the graft copolymer’s structure, various interactions between the components in the blend will be established, resulting in better adhesion which implicates improvement of compatibility in blends. Also, from the results, it can be seen that differences in structures of the added compatibilizer are clearly reflected in the adhesion parameters results, making this an acceptable method to determine whether two polymers are compatible. Morphology of the blends with the graft copolymers is significantly finer and the dispersed size is more uniformly distributed in comparison to the neat SAN/EPDM blend. The conditions of the optimal adhesion parameters with compatibilizer location at the interface, predicting by the thermodynamical models, correlated well with the improvement of the morphology and thermal measurements.     

Thermal behavior and shape memory properties of PCL blends film with PVC and PMMA polymers

Iranian Polymer Journal - Shape memory polymers have attracted extensive attention attributable to their characteristics and abundant applications. In this study, shape memory behavior and...     

Small-angle scattering studies of PVC and PVC blends

Small-angle X-ray and small-angle neutron scattering studies have been carried out on poly(vinyl chloride) (PVC), and blends of PVC with solution-chlorinated polyethylene (SCPE) and poly(butyl acrylate) (PBA). The PVC used was commercial (suspension-polymerized) or bulk-polymerized. The blends of PVC with PBA were prepared by solvent-casting and those with SCPE by in situ polymerization. PVC samples show shoulders in the scattering spectra, presumably due to crystallites, which persist even in samples which have been solvent cast. Blends of PVC with PBA also show a peak but at a higher ‘d’ spacing. The blends with SCPE which were prepared by in situ polymerization show no such peak. This suggests that the method of preparation prevents the formation of crystallites. An increase in scattering of the PBA blends was observed when the samples were heated to the temperature of phase separation. Neutron scattering studies were also carried out using 2% deuterium labelled PVC in PVC and in the blends. In the PVC this showed chain dimensions in good agreement with predicted values. In the blends, dimensions of the same order were obtained, confirming a molecular dispersion of chains in the single phase, but there was an apparent reduction in the chain dimensions. This could be explained by a true reduction in dimensions or a non-zero A₂ value in the blends.     

Studies on impact modification and fractography of solution cast blends of PVC and NR/PU block copolymers

Segmented polyurethanes based on toluene diisocyanate (TDI) with three different chain extender diols, viz., propylene glycol (PG), 1,4-butanediol (1,4-BDO), and 1,3-butanediol (1,3-BDO) were synthesized by a two-step, solution polymerization method. These different NR-b-PU block copolymers were incorporated into PVC at various compositions by the solution blending method. These blend systems were subjected to FTIR analysis, DSC, tensile testing, tensile impact measurements, and tensile impact fracture studies by SEM. It was observed that systems showed modification in tensile impact properties. Optimum impact properties were shown at concentrations 6–8% of the block copolymer. At higher compositions there is deterioration in impact properties. High impact properties showed by these blends are attributed to the optimum level of compatibility achieved between the blend components. Tensile impact fracture studies revealed that failure pattern for these blend system transitioned from brittle to ductile fracture. Blends up to 10 wt% of block copolymer showed partially compatible heterogeneous nature exhibiting domain morphology. Blends with higher block copolymer content showed deterioration in tensile strength, modulus, yield strength, and tensile impact strength due to higher particle size of the agglomerated rubber soft segments of the block copolymer.     

Peel adhesion of PVC to steel

The adhesion of PVC to various steel surfaces has been studied using a simple peel test apparatus. The effects of surface cleanliness, phosphate coatings, and oxide films on adhesion have been studied, and studies of oxide film thickness indicate that forces other than those usually considered in models of adhesion may be operative.     

Effects of organoclay on the compatibility and interfacial phenomena of PE/EVA blends with UCST phase behavior

The compatibilization effects of organically modified nanoclay on the miscibility window, phase separation kinetics, biphasic morphology, interfacial tension, and final properties of polyethylene/ethylene vinyl acetate copolymer blends exhibiting UCST behavior have been investigated. Regardless of blend composition, intercalated nanoclay decreases the phase transition temperatures to lower values and changes the symmetry of phase diagram. The miscibility of PE and EVA phases in the amorphous regions of nanocomposites noticeably enhances and finer biphasic morphology is obtained by the incorporation of organoclay. The pinning influence of the nanofiller on polymer chain diffusion causes much slower phase separation kinetics for the nanocomposites. Similar to conventional compatibilizers such as block copolymers, the interfacial activity of nanoclay leads to a sharp decline in the interfacial tension of PE/EVA up to 2‐orders of magnitude. Moreover, the results show that imposing restrictions on the phase separation phenomenon increases the impact strength of the virgin blend and related nanocomposite. However, this improvement has been much more noticeable in the presence of nanoparticles, which is due to the simultaneous roles of organoclay as an effective compatibilizer and reinforcement. POLYM. COMPOS., 35:2329–2342, 2014. © 2014 Society of Plastics Engineers     

Processing and mechanical properties of recycled PVC and of homopolymer blends with virgin PVC

Mechanical and processing properties of recycled polyvinylchloride (PVC, from bottles and pipes) were compared with those of virgin pipe grade PVC. Blends of recycled and pipe grade PVC were also prepared and characterized. It was found that the particle size and the restabilization of the recycled PVC are the two main points to be considered for obtaining virgin/recycled PVC blends with uniform and good mechanical properties. In general, recycled PVC not only does not significantly reduce the modulus and tensile strength, but also improves the impact strength and processing behavior of pipe grade virgin PVC. Only the thermomechanical resistance is slightly lowered. The latter points hold, of course, only when the recycled PVC contains both reinforcing and modifier agents. © 1996 John Wiley & Sons, Inc.     

PVC／PU合金的制备与研究

叙述了选择混炼型聚氨酯(PU)与分子量适中的Ⅱ型聚氯乙烯(PVC)树脂制备PVC/PU合金的过程,讨论了PVC/PU共混比、填充剂、硫化体系、共混工艺等因素对PVC/PU合金性能的影响。结果表明:选择PVC/PU=60/40(质量比),硫化剂TD15份,白炭黑30份,混炼温度140—160℃,可制得性能优良的PVC/PU合金。动态力学性能实验显示了PVC/PU合金有较好的相容性。     

Crosslinking of PVC and NBR blends

The purpose of our work is to control the interfacial bonds between PVC and NBR using the ammonium salts of triazine thiols and dithiodimorpholine (DTDM) and thereby reveal the relation between the interfacial bonds and the final mechanical properties of products. In the experimental work a two-stage process was used. At first, an NBR/PVC blend was mixed with a mono-tetra-n-butylammonium salt of triazine trithiol at a temperature of 100°C on a two-roll mill to give the branching structure of triazine thiols into PVC. In the second stage branched NBR/PVC reacted with DTDM to afford the branched PVC containing trithiomorphonyl groups. In the presence of ZnO at 160°C trithiomorphonyl groups react with NBR to form a crosslinking structure between NBR and PVC. The mechanical properties of cured NBR/PVC blends were markedly improved by the treatment process and after addition of tetramethylthiuram monosulphide also. The mechanical properties were not improved by increasing the concentration of TT-TBA (tetrabutylammonium salt of 1,3,5-triazine-2,4,6-trithiol) over 4.2 phr.     

Effect of matrix composition on the fracture behavior of rubber-modified PMMA/PVC blends

Summary PB-g-MMA core-shell impact modifiers were synthesized by seed emulsion polymerization and impact-modified PMMA/PVC blends were prepared by melt blending PMMA, PVC and PB-g-MMA at 160 °C. The PB-g-MMA particles were dispersed uniformly in the PMMA/PVC matrix. PMMA/PVC blends were prepared in the blend ratio from 100/0 to 0/100 and the rubber content was kept 16% in all the compositions. The effects of matrix composition on the mechanical properties and morphology of the blends were studied. It was found that when the matrix was a PMMA-rich system, the sample broke in a brittle mode and crazing of the matrix was the main mechanisms of deformation. When the matrix was a PVC-rich system, the sample broke in a ductile mode and the main deformation mechanisms were cavitation of the particle and shear yielding of the matrix. There existed a transition from crazing to shear yielding in the rubber-modified PMMA/PVC blend as the matrix composition varied.     

Rheological behavior and morphology of blends of copolymers of α-methylstyrene-co-acrylate with PVC

The copolymers of poly(α-methyl styrene–methyl acrylate) (PMSMA) and poly(α-methyl styrene–ethyl acrylate) (PMSEA) were synthesized by emulsion polymerization. The compatibility of these copolymers with poly(vinyl chloride) (PVC) was estimated by the solubility parameter method and scanning electron microscopy (SEM). The rheological behavior was investigated by a flow tester. The mechanical properties, rheological behavior, and morphology of these blends show that these copolymers can be used as a processing aid for PVC. © 1996 John Wiley & Sons, Inc.     

The melt compatibility of blends of polypropylene and ethylene-propylene copolymers

Blends of polypropylene with ethylene-propylene copolymers of various compositions have been studied by small angle neutron scattering with regard to their compatibility at room temperature and in the melt. It has long been known that such blends separate into distinct phases at lower temperatures due to the crystallinity of the isotactic polypropylene, The work described herein has shown that these blends are also immiscible in the melt, even where the ethylene content of the copolymer is as low as 8 percent. Moreover, the separated phase domains grew rapidly at melt temperatures. Blends of atactic polypropylene with isotactic polypropylene did become miscible upon melting.     

On the compatibility of polysaccharide/maleic copolymer blends. II. Thermal behavior of pullulan‐containing blends

The compatibility of pullulan with maleic acid/vinyl acetate copolymers in the solid state in the form of thin films was studied with thermogravimetry, differential scanning calorimetry, infrared spectroscopy, and optical microscopy. With respect to morphology, blends with a content of pullulan greater than 85 wt % exhibited an even distribution of finely dispersed particles. The thermal properties were dependent on the mixing ratio, and the interactions between components were quite pronounced in the pullulan‐rich blends. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1782–1791, 2002