Toughness,dynamic mechanical property,and morphology of polyvinylchloride/acrylonitrile‐styrene‐butyl acrylate blends

Acrylonitrile‐styrene‐butyl acrylate (ASA) graft copolymers with different acrylonitrile (AN) contents, the core‐shell ratio, and tert‐dodecyl mercaptan (TDDM) amounts were synthesized by seed emulsion polymerization. Polyvinylchloride (PVC)/ASA blends were prepared by melt blending ASA graft copolymers with PVC resin. Then the toughness, dynamic mechanical property, and morphology of the PVC/ASA blends were investigated. The results indicated that the impact strength of the PVC/ASA blends increased and then decreased with the increase of the AN content in poly(styrene‐co‐acrylonitrile (SAN) copolymer, and increased with the increase of the core‐shell ratio of ASA. It was shown that brittle‐ductile transition of PVC/ASA blends was dependent on poly(butyl acrylate) (PBA) rubber content in blends and independent of AN content in SAN copolymer. The introduction of TDDM made the toughness of PVC/ASA blends poor. Dynamic mechanical analysis (DMA) curves exhibited that PVC and SAN copolymers were immiscible over the entire AN composition range. From scanning electron microscopy (SEM), it was found that the dispersion of ASA in PVC/ASA blends was dependent on the AN content in SAN copolymer and TDDM amounts. J. VINYL ADDIT. TECHNOL., 22:43–50, 2016. © 2014 Society of Plastics Engineers     

Studies on the polyblends of poly(vinyl chloride) with various methacrylate copolymers,melt rheological properties. II

Studies have been made on the melt rheological properties of poly(vinyl chloride) (PVC) with copolymers of methyl methacrylate (MMA) and methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA), and 2-ethyl hexyl acrylate (EHA) at a blending ratio of 80:20. Effect of blend composition on shear stress–shear rate, melt viscosity, melt elasticity, and extrudate distortion have been studied. A significant decrease in the melt viscosity is observed on incorporation of low T_g, acrylate copolymers such as those with BA and EHA, thereby reducing the processing temperature. First normal stress and die swell ratio also decreases with an increase in the side chains of acrylate copolymer. PVC blended with P(MMA-co-BA) and P(MMA-co-EHA) is sensitive to both temperature and shear stress.     

异戊二烯-丙烯酸酯类共聚弹性体的制备及其对PVC的增韧作用

研究了苯乙烯(ST)、甲基丙烯酸甲酯(MMA)为壳层单体,丙烯酸丁酯(BA)、异戊二烯(IP)、丙烯酸(AA)为核单体,以乳液聚合工艺制备共聚乳液和弹性体树脂,制备了共聚树脂与PVC的共混材料。研究了乳化剂、引发剂、反应温度对弹性体特征黏度的影响,对共聚物结构进行了表征,并测试了共混材料的流变性能和机械性能。结果表明:乳化剂4.5%,引发剂0.5%时,其共聚物的特性黏度最高。当m(共聚弹性体)∶m(PVC)=10∶100时,冲击强度达到了48.67 kJ.m-2。     

Investigation of multiphase polymeric systems of PVC

Graft copolymers of chlororubber-20-g-(ethylacrylate-co-acrylonitrile (2:1)) and chlororubber-20-g-(styrene-co-vinyl acetate-co-acrylonitrile [1:1:1]) have been synthesized by solution precipitation polymerization technique. The graft copolymers have been characterized by elemental analysis, IR spectroscopy, and viscometry. The graft copolymers have been melt blended with PVC. The mechanical properties, such as flexural, tensile strength, and impact strength, of the blends have been studied to evaluate the relative performance of various graft copolymer blends of PVC as impact modified systems. Mechanical properties of the blends have been discussed in terms of morphology of impact fractured samples.     

含氟PVC共聚树脂性能的研究

研究了含氟单体的种类及用量对PVC共聚树脂的物理性能及其共混料加工性能的影响,结果表明:①在丙烯酸六氟丁酯、丙烯酸十二氟庚酯、丙烯酸十三氟辛酯3种单体中,采用丙烯酸六氟丁酯制备的含氟PVC共聚树脂共混料的熔融因数F最高;丙烯酸六氟丁酯的最佳用量为每100 g VCM加入1 g。②含氟PVC共聚树脂的表观密度、增塑剂吸收量、热稳定时间,其共混料的塑化时间、平衡转矩、熔融因数F等指标均优于空白样。     

n‐Butyl acrylate based latex interpenetrating polymer networks used as processing modifiers and impact modifiers of poly(vinyl chloride)

A latex interpenetrating polymer network (LIPN), consisting of poly(n‐butyl acrylate), poly(n‐butyl acrylate‐co‐ethylhexyl acrylate), and poly(methyl methacrylate‐co‐ethyl acrylate) and labeled PBEM, with 1,4‐butanediol diacrylate as a crosslinking agent was synthesized by three‐stage emulsion polymerization. The initial poly(n‐butyl acrylate) latex was agglomerated by a polymer latex containing an acrylic acid residue and then was encapsulated by poly(n‐butyl acrylate‐co‐ethylhexyl acrylate) and poly(methyl methacrylate‐co‐ethyl acrylate). A polyblend of poly(vinyl chloride) (PVC) and PBEM was prepared through the blending of PVC and PBEM. The morphology and properties of the polyblend were studied. The experimental results showed that the processability and impact resistance of PVC could be enhanced considerably by the blending of 6–10 phr PBEM. This three‐stage LIPN PBEM is a promising modifier for manufacturing rigid PVC. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1168–1173, 2004     

Investigation on multiphase polymeric systems of poly(vinyl chloride). I. PVC–chlororubber-20-gp-styrene–acrylonitrile (2 : 1) blends

A graft copolymer [chlororubber-20-gp-styrene–acrylonitrile (2 : 1)] has been synthesized by a solution precipitation polymerization technique grafting styrene and acrylonitrile onto chlororubber-20 main chain. The graft copolymer has been characterised by elemental analysis, IR spectroscopy, and viscometry. It has been blended with PVC by melt mixing using a Brabender plasticorder and extrusiograph. The mechanical properties such as flexural and tensile strengths and impact strength of the blends have been studied to evaluate its performance as an impact modifier. The behavior of PVC–chlororubber-20-gp–styrene-acrylonitrile (2 : 1) blends has also been compared with PVC–chlororubber-20 and PVC–KM-365B (a commercial acrylate modifier) blends. The thermal behavior of these blends has also been studied. It has been found that PVC–chlororubber-20-gp-styrene–acrylonitrile (2 : 1) blends have higher impact strength than PVC–chlororubber-20-gp blends though the PVC–KM-365B blends have the highest impact strength. Based on the authors' previous compatibility studies along with present X-ray diffraction studies and the morphological investigation of the fractured surface by scanning electron microscopy, the mechanical behavior of these blends have been explained in the framework of existing theories. A model has been proposed to account for the optimum dispersion and adhesion of graft polyblends of chlororubber-20 in PVC matrix.     

高密度聚乙烯／尼龙1010共混体系的研究

采用接枝共聚方法,合成了高密度聚乙烯与马来酸酐,甲基丙烯酸和丙烯酸丁酯的接枝共聚物增容剂,研究了增容剂中接枝单体的种类及含量和增容剂用量等因素对高密度聚乙烯／尼龙1010共混体系力学性能的影响,结果表明在不同类型的接枝共聚物中以聚乙烯马来酸酐接枝共聚物对HDPE／PA1010共混体系的增容效果最好,在接枝单体含量和增容剂用量分别为4％－6％和5％左右时,共混体系的力学性能最好。     

Studies on polymer blends. II. Butadiene–styrene copolymers and polybutadiene–polystyrene blends

The properties of butadiene–styrene copolymers and of polybutadiene–polystyrene blends were compared. Polybutadiene, polystyrene, and four copolymers having styrene contents of 20, 40, 60, and 80% were prepared. The copolymers were compared with blends having various styrene contents and prepared by means of latex blending and roll blending. Vulcanizates were prepared by three different curing methods, i.e., sulfur cure, peroxide cure, and radiation cure. The results of the benzene extraction of three vulcanizates showed that the polystyrene blended was not cured by any of the curing methods used. The properties of the vulcanizates of the copolymers were markedly different from those of the blends, i.e., in the case of the blends the properties showed a linear relationship with their blending ratio, while in the copolymers the properties showed a curvilinear relationship which had an inflection point at a styrene content of about 60%. From this phenomenon of the copolymers, it was proposed that the second-order transition point of styrene is the cause of the properties showing this peculiar point. From the results, it was found that the behavior of styrene in copolymers is essentially different from that in blends.     

‘Elasticisation’ and plasticisation of PVC with ethylene-vinyl acetate copolymers

Copolymers of ethylene and vinyl acetate (E-VA) of a certain composition can be used for the improvement of impact properties (elasticisation) of PVC as well as under certain conditions (grafting) for the preparation of flexible PVC (plasticisation). Products of interesting properties are prepared by blending E-VA (up to ～ 12%) with PVC or more advantageously by grafting vinyl chloride on special E-VA types. Graft copolymerisation by the suspension method allows the synthesis of E-VA/PVC systems in all ratios (up to 80% E-VA); these polymers are compatible over the whole range in contrast to the blends. Studies on the grafting efficiency of some monomers show that vinyl chloride can be grafted readily on E-VA. The grafting process is performed on a technical scale to give PVC types with E-VA contents up to 50%. Products with 6–8% E-VA should be classified as impact-modified suspension PVC. Flexible types (40–60% E-VA) have properties of flexible PVC with the plasticiser chemically incorporated, but may also be blended with unmodified PVC to give impact-improved formulations. The properties of the elasticised PVC (8% E-VA) mainly depend on the vinyl acetate (V-OAc) content of the E-VA and its molecular weight. Levapren® 450 P (45% V-OAc; mol. wt. ～ 100,000), a solution process copolymer, has good elasticising efficiency in blends and graft copolymers with PVC. PVC/E-VA products may be processed with or without addition of uncombined PVC into rigid or flexible PVC by the usual methods of PVC technology, e.g. extrusion, injection moulding, blow-moulding and calendering. Competitive modifiers, such as acrylonitrile-butadiene-styrene copolymers, methacrylate-butadiene-styrene copolymers, acrylates or chlorinated polyethylene, are compared with E-VA. Levapren® 450 P shows high efficiency as an impact modifier even in low concentration, giving good processability and ageing behaviour. Glass-clear high-impact PVC cannot be obtained by E-VA modification. Some electron microscopy studies to characterise the distribution of E-VA in the resin phase (PVC) are described; these showed the presence of a two-phase system.     

NBR/PVC共混胶的结构与性能

采用机械共混法和乳液共沉法制备了NBR/PVC共混胶,通过差示扫描量热仪(DSC)和场发射扫描电子显微镜(FE-SEM)对共混胶的微观形貌、结构进行了表征,考察了共混方式和共混胶配比对其力学性能的影响,并比较了共混胶、CPE、P-83对硬质/软质PVC的改性效果。结果表明:①与机械共混胶相比,乳液共沉胶混合得更均匀,分散性更好,其分子级混合程度更好;②乳液共沉胶试样的力学性能在总体上优于机械共混胶;③对于硬质PVC,CPE的改性效果优于其他改性剂;④对于软质PVC,乳液共沉胶的改性效果最好,特别是对撕裂强度的提高非常明显。     

有机锡参与合成P(BA-EHA)/PVC及共混改性PVC的结构与性能

通过种子乳液聚合方法,采用丙烯酸丁酯(BA)、丙烯酸2-乙基己酯(EHA)为核层单体,与少量有机锡单体共聚制备了含有机锡的P(BA-EHA)胶乳,与氯乙烯(VC)乳液接枝共聚合成了P(BA-EHA)/PVC复合改性剂。通过透射电子显微镜(TEM)、动态力学分析仪(DMA)、扫描电子显微镜(SEM)等测试手段,考察了复合乳胶粒子和共混材料的形态结构、复合改性剂中有机锡含量对其共混改性PVC材料的力学性能及复合粒子热稳定性的影响。DMA和TEM分析结果表明:复合粒子的加入显著改善了橡胶相与PVC之间的相容性,P(BA-EHA)在PVC基体中具有很好的分散性和均匀度,SEM照片显示共混材料缺口断面表现为优异的基体屈服型断裂韧性。     

Synthesis and characterization of poly(butyl acrylate‐co‐ethylhexyl acrylate)/ poly(vinyl chloride)[P(BA‐EHA)/PVC] novel core‐shell modifier and its impact modification for a poly(vinyl chloride)‐based blend

Synthesis of poly(butyl acrylate‐co‐ethylhexyl acrylate)‐core/poly(vinyl chloride)‐shell [P(BA‐EHA)/PVC] used as a modifying agent of PVC via semicontinuous seeded emulsion copolymerization is reported here. Diameter distributions and morphology of the composite latex particles were characterized with the aid of particle size analyzer and transmission electron microscopy (TEM). The grafting efficiency (GE) and grafting ratio (GR) of vinyl chloride (VC) grafted onto the P(BA‐EHA) with varying content of crosslinking agent and core‐shell ratios were investigated. TEM studies indicated that the P(BA‐EHA)/PVC latex particles have core‐shell structure, and the P(BA‐EHA) rubbery particles in blending materials were uniformly dispersed in PVC matrix. Dynamic mechanical analysis (DMA) results revealed that the compatibility between the P(BA‐EHA) and the PVC matrix was significantly improved due to the presence of the P(BA‐EHA)‐grafted‐VC copolymer. The notched impact strength of the blending material with 3 wt% of rubber content was seven times that of the PVC. Linear regressions of mechanical properties as loading of the modifier were made. The resulting data of notched impact strength and elongation at break for the blending materials deviated significantly from regression lines within 3–4.5 wt% of the P(BA‐EHA) content. The PVC blends modified by the modifier exhibited good toughness and easy processability. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers     

表面处理对木粉增强PVC发泡复合板材性能的影响

研究表面处理的木粉对发泡聚氯乙烯(PVC)板材的增强改性效果。使用铝酸酯偶联剂、丙烯酸丁酯预聚物对木粉进行表面处理，将其混合到聚氯乙烯发泡板材配料中进行板材加工生产，结果表明，经处理的木粉能提高发泡PVC板材的拉伸强度和冲击强度。用铝酸酯偶联剂处理木粉的发泡板材力学性能好于用丙烯酸丁酯预聚物处理的板材；而用丙烯酸丁酯预聚物处理木粉的复合材料在流变加工性能优于用铝酸酯处理木粉的复合材料。     

PVC modification through polymerization of a monomer absorbed in porous suspension‐type PVC particles

In‐situ polymerization is the polymerization of one monomer in the presence of another polymer. It can be performed by sequential emulsion polymerization, or by reactions in the melt, in the solid phase, or in solution. The current report describes two methods to obtain poly(vinyl chloride) (PVC) modification through polymerization of a monomer absorbed in commercial porous suspension‐type PVC particles. The generated modified PVC products differ significantly in their structure and properties. The first approach includes absorption of a monomer/peroxide solution within porous suspension‐type PVC particles, followed by polymerization/crosslinking in the solid state at 80°C in an aqueous stabilizer‐free dispersion. The monomer/crosslinker pairs selected are styrene/DVB (divinyl benzene), methylmethacrylate/EGDMA (ethylene glycol dimethacrylate), butyl acrylate/EGDMA, and ethylhexyl acrylate/EGDMA. The influence of composition and nature of the polymerizing/crosslinking constituents on the modified PVC particle structure was studied by microscopy methods, porosity measurements, and dynamic mechanical behavior (DMTA). The level of molecular grafting between PVC and the modifying polymer was determined by solvent extraction experiments. This work shows that the different monomers used represent distinct courses of monomer transport through the PVC particles. The characteristics of the modified PVC particle indicate that the polymerization/crosslinking process occurs in both the PVC bulk, i.e., within the walls constituting a particle, and in the PVC pores. No indication of chemical intermolecular interaction within the modified PVC particles was found. In the second approach, a solution of monomer, initiator, and a crosslinking agent is absorbed in commercial suspension‐type porous PVC particles, thus forming a dry blend. This dry blend is subsequently reactively polymerized in a twin‐screw extruder at an elevated temperature, 180°C, in the molten state. The properties of the reactively extruded PVC/PMMA blends are compared with those of physical blends at similar compositions. Owing to the high polymerization temperature, short‐chain polymers are formed in the reactive polymerization process. Reactively extruded PVC/PMMA blends are transparent, form single‐phase morphology, have a single T_g, and show mechanical properties comparable with those of the neat PVC. The resulting reactively extruded PVC/PMMA blends have high compatibility. J. Vinyl Addit. Technol. 10:109–120, 2004. © 2004 Society of Plastics Engineers.     

Miscibility and rheological properties of poly(vinyl chloride)/styrene–acrylonitrile blends prepared by melt extrusion

Styrene–acrylonitrile (SAN) with acrylonitrile (AN) concentrations of 11.6–26 wt % and α‐methylstyrene acrylonitrile (αMSAN) with a wide range of AN concentrations are miscible with poly(vinyl chloride) (PVC) through solution blending. Here we examine the rheological properties and miscibility of PVC/SAN and PVC/αMSAN blends prepared by melt extrusion for commercial applications. We have investigated the rheological properties of the blends with a rheometer and a melt indexer. The PVC/SAN and PVC/αMSAN blends have a low melting torque, a long degradation time, and a high melt index, and this means that they have better processability than pure PVC. The miscibility of the blends has been characterized with differential scanning calorimetry, dynamic mechanical thermal analysis, and advanced rheometrics expansion system analysis. The miscibility of the blends has also been characterized with scanning electron microscopy. The SAN series with AN concentrations of 24–31 wt % is immiscible with PVC by melt extrusion, whereas αMSAN with 31 wt % AN is miscible with PVC, even when they are blended by melt extrusion, because of the strong interaction between PVC and αMSAN. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

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.     

Properties of poly(vinyl chloride) blended with an emulsion copolymer of N‐cyclohexylmaleimide and methyl methacrylate

Emulsion‐polymerized copolymers of methyl methacrylate and N‐cyclohexylmaleimide were synthesized and used for blending with poly(vinyl chloride) (PVC) to improve the heat resistance of PVC. The thermal stabilities of the blends with different copolymer contents were characterized by thermogravimetric analysis, torsional braid analysis, and the Vicat softening temperature. The mechanical properties and rheological behavior of the blends were also determined. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 201–205, 2003     

PUR-T／PVC热塑性弹性体的制备及工艺探究

以热塑性聚氨酯弹性体(PUR–T)、聚氯乙烯(PVC)为主要原材料,通过熔融共混挤出制备PUR–T／PVC共混热塑性弹性体。讨论了PUR–T／PVC共混比、增塑剂用量、挤出共混温度、螺杆转速对共混弹性体性能的影响,利用万能试验机、扫描电子显微镜、转矩流变仪、旋转流变仪等研究了弹性体的加工性能及结构。结果表明,当PUR–T／PVC共混比为70／30,增塑剂邻苯二甲酸二辛酯用量为20份,挤出温度为160℃,螺杆转速为330 r／min时,弹性体材料的综合性能最佳;共混弹性体的表观黏度小于纯PUR–T,PVC含量在20%～50%时,PVC易形成网络结构。     

The in situ polymerization of vinyl chloride in poly(butyl acrylate)

The in situ polymerization of vinyl chloride with poly(butyl acrylate) has been studied. Vinyl chloride was polymerized using a peroxydicarbonate initiator in sealed ampoules in the presence of various weights of poly(butyl acrylate). The products were examined by dynamic mechanical analysis and electron microscopy. It was found that if about 50% or less vinyl chloride was present in the mixture homogeneous blends were formed. If more than 50% vinyl chloride was present the polymerization passed through a two phase region in the three component phase diagram and inhomogeneous blends were formed. If homogeneous blends prepared as above were reswollen with vinyl chloride and the latter polymerized, then homogeneous blends containing more poly(vinyl chloride) could be prepared, avoiding the two phase region. The interaction parameters between vinyl chloride and both poly(vinyl chloride) and poly(butyl acrylate) were estimated using inverse gas chromatography. Using these and an estimate of the polymer/polymer interaction parameter the three component phase diagram could be qualitatively explained.