The miscibility of polyacrylates and polymethacrylates with PVC: In situ polymerization and the miscibility of poly(methyl acrylate) and poly(ethyl acrylate) with PVC

The in situ polymerization of vinyl chloride with various polyacrylates and polymethacrylates has been studied. The products were examined by dynamic mechanical analysis. Poly(methyl acrylate) and poly(ethyl acrylate) had previously produced two-phase blends with poly(vinyl chloride) (PVC) by solvent casting, but poly(ethyl acrylate) was shown to be miscible with PVC when blends were produced by in situ polymerization. Poly(methyl acrylate) and poly(octyl acrylate) were found to be immiscible with PVC whereas other polyacrylates and polymethacrylates with intermediate ester group concentrations were found to be miscible, confirming previous studies. The glass transition temperatures of the blends were measured and the deviations from the expected mean of the two base polymers were calculated as an indication of the strength of interaction between the polymers. The polymers having intermediate ester group concentrations showed the strongest interactions and the results correlated well with previously measured interaction parameters.     

Compatibility of polyacrylates and polymethacrylates with poly(vinyl chloride): 2. Measurement of interaction parameters

Interactions of various solvents with poly(vinyl chloride) and a series of polyacrylates and polymethacrylates have been studied by inverse gas chromatography. Values of the interaction parameters χ₁₂ have been calculated and show the importance of specific interactions between the polymers and the solvents. Low values of χ₁₂ indicating a strong interaction were found for the polyacrylates and polymethacrylates with a proton donating solvent, chloroform, and for the poly(vinyl chloride) with some proton accepting solvents, especially butan-2-one. Interactions of solvents, with mixtures of poly(vinyl chloride) with some compatible polyacrylates and polymethacrylates, have also been studied. From this, and using the values of χ₁₂ found above, values of the polymer-polymer interaction parameters χ₂₃ have been calculated. Low values of χ₂₃, indicating a strong interaction were found, especially for polymethacrylates and polyacrylates with shorter ester side chains. Lower values were obtained for polymethacrylates than polyacrylates again indicating greater interactions. These results fit in well with the results of a previous paper where we found that the polymers with longer ester side chains were not compatible with PVC or phase separated on heating, and that fewer acrylates than methacrylates are compatible with PVC.     

Studies on the polyblends of poly(vinyl chloride) with various methacrylate copolymers,physical and mechanical properties. I

The effect of blending various methacrylate copolymers on the physical and mechanical properties of poly(vinyl chloride) (PVC) has been investigated. Copolymers of methylmethacrylate with methylacrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate in 80:20 and 50:50 wit methylmethacrylate have been prepared and characterized by nuclear magnetic resonance spectroscopy. Polyblends of PVC and such polyacrylates have been prepared in 80:20 ratio by melt blending technique and characterized by thermomechanical analysis to study the glass transition behavior vis-à-vis the compatibility of these blends. Mechanical properties of these blends revealed a substantial increase in impact strength particularly when long chain acrylate polymers like butyl acrylate and 2-ethyl hexyl acrylates are used; however, there is a decrease in the yield stress and initial modulus. A shift from brittle failure to ductility has been observed in blends of PVC on incorporation of these acrylate copolymers. Scanning electron microscopic studies have been carried out to support these observations.     

The miscibility of polyacrylates and polymethacrylates with PVC: An interpretation of the heats of mixing of oligomers

Oligomers of various polyacrylates and polymethacrylates and a chlorinated paraffin (as an analogue for PVC) were studied in order to give information relevant to the miscibility of the respective polymers. The heats of mixing of the oligomers with the chlorinated paraffin were measured and showed that those oligomers with the lowest and highest ester group concentration (poly(methyl acrylate) and poly(octadecyl methacrylate)) had unfavourable (positive) heats of mixing whereas oligomers with intermediate ester group concentrations had favourable (negative) heats of mixing. This was consistent with the miscibility of the respective polymers in most cases. The results were interpreted in terms of the summation of the effects of the specific interactions and the dispersive forces. A high concentration of interacting groups leads to a high contribution from the specific interaction, but in the case of poly(methyl acrylate) with the highest concentration of interacting groups this is outweighed by a large unfavourable contribution from the dispersive forces.     

In-situ polymerization of n-butyl acrylate in poly(vinyl chloride)

The in situ polymerization of n-butyl acrylate with poly(vinyl chloride) has been studied. Butyl acrylate was polymerized using a peroxydicarbonate initiator and a thiol chain transfer agent in the presence of poly (vinyl chloride) beads suspended in water. The products were examined, after pressing into sheets, for optical clarity and by dynamic mechanical analysis. It was found that if 10% butyl acrylate was peesent in the mixture homogeneous blends were formed but if 15% or more butyl acrylate was present two phase mixtures were formed. If homogeneous blends prepared as above were reswollen in butyl acrylate, and the latter then polymerized, homogeneous blends containing more poly(butyl acrylate) could be prepared. The interaction parameters between both poly(vinyl chloride' and poly(butyl acrylate) and butyl acrylate were estimated by inverse gas chromatography. Using these and an estimate of the polymer/polymer interaction parameter the three component phase diagram could be qualitatively explained.     

Effect of copolymer composition on the miscibility of blends of styrene-acrylonitrile copolymers with poly (methyl methacrylate)

The phase behaviour for blends of various polymethacrylates with styrene-acrylonitrile (SAN) copolymers has been examined as a function of the acrylonitrile content of the copolymer. Poly(methyl methacrylate), poly(ethyl methacrylate) and poly(n-propyl methacrylate) were found to be miscible with SANs over a limited window of acrylonitrile contents while no SANs appear to be miscible with poly(isopropyl methacrylate) or poly(n-butyl methacrylate). These conclusions were reached on the basis of lower critical solution temperature (LCST) and glass transition temperature behaviour. All miscible blends exhibited phase separation on heating, LCST behaviour, at temperatures which varied greatly with copolymer composition. An optimum acrylonitrile (AN) level ranging from about 10 to 14% by weight resulted in the highest temperatures for phase separation which has important implications for selection of SANs to produce homogeneous mixtures by melt processing. The basis for miscibility in these systems is evidently repulsion between styrene and acrylonitrile units in the copolymer as explained by recent models. The excess volumes for all blends are zero within experimental accuracy which suggests that the interactions for miscibility are relatively weak even for the optimum AN level. This interaction becomes smaller the larger or more bulky is the alkyl side group of the polymethacrylate.     

共混聚合物体系的静电纺丝及其混容性研究

分别将聚醚砜酮(PPESK)/聚苯乙烯(PS)不相容体系溶于N,N-二甲基乙酰胺或N-甲基吡咯烷酮与四氢呋喃的混合溶剂,聚甲基丙烯酸甲酯(PMMA)/聚丙烯酸甲酯(PMA)相容体系溶于丁酮,搅拌得到聚合物共混溶液进行静电纺丝和浇铸成膜。研究了浇铸膜与电纺纤维膜的微观结构与力学性能。结果表明:静电纺丝改善了不相容体系的混容性,而未改变相容体系的混容性;溶剂对电纺纤维的微观结构以及力学性能有所影响。     

Flexibilität und thermodynamische Eigenschaften von Polyacrylaten,Polymethacrylaten und statistischen Acrylat/Methacrylat-Copolymeren 2. knäuelparameter

Flexibility and interaction parameters of the polymers have been calculated from the results of light-scattering and viscosity measurements with polyacrylates, polymethacrylates and random copolymers of methyl methacrylate with acrylates and n-butyl methacrylate. Only slight differences are found when the chain rigidity of polyacrylates is compared with that of polymethacrylates. There is however a clearcinfluence of the ester alkylgroup. With increasing size of the ester alcohol the polymer chain gets more rigid. In case of copolymers the chain flexibility does not result simply from the homopolymer values. The measured values don't reveal a systematic connection, moreover in case of copolymers there is a strong influence of solvents on the unperturbed dimensions. The repulsive powers occuring in the copolymer coil due to hetero-contacts have been characterized quantitatively. The graduaeion which was found coincides with compatibility tests of the corresponding homopolymers in a concentrated solution : the more intense the expansion of the copolymer coil caused by heterocontacts, the lower the concentration where a demixing of the homopolymers is observed.     

Synthesis and evaluation of poly(dioctyltin maleate‐styrene‐methyl acrylate) as a stabilizer for poly(vinyl chloride)

A novel thermal stabilizer poly(dioctyltin maleate‐styrene‐methyl acrylate) [P(DOTM‐St‐MA)] was synthesized by radical solution polymerization with benzene as the solvent and 2,2‐azobisisobutyronitrile as the initiator. The structure of terpolymer was characterized by FTIR and ¹H‐NMR spectra, and thermal stability of the stabilizer was measured by thermogravimetric analysis (TGA). Evaluation of [P(DOTM‐St‐MA)] as thermal stabilizer for poly(vinyl chloride) (PVC) was measured by acidimeter, and the extent of changing color of PVC was measured by thermal aging method. Compatibilities of four stabilizers with PVC were characterized by scanning electron microscope (SEM). The results showed that, with the same tin content in PVC mixtures, [P(DOTM‐St‐MA)] exhibited better performance as a PVC stabilizer compared with other stabilizers,such as poly(dibutylin maleate‐styrene‐methyl acrylate), DOTM, and dibutylin maleate (DBTM). Furthermore, [P(DOTM‐St‐MA)] had better compatibility with PVC in PVC processing. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effects of compatibilizing agents in poly(n-butyl acrylate)/poly(methyl methacrylate) composite latexes

Graft copolymers with poly(n-butyl acrylate) (PBA) backbones and poly(methyl methacrylate) (PMMA) macromonomer side chains are used as compatibilizing agents for PBA/PMMA composite latexes. The composite latexes are prepared by seeded emulsion polymerization of methyl methacrylate (MMA) in the presence of PBA particles. Graft copolymers were already incorporated into the PBA particles prior to using these particles as seed via miniemulsion (co)polymerization of n-butyl acrylate (BA) in the presence of the macromonomers. Comparison between size averages of composite and seed particles indicates no secondary nucleation of MMA during seeded emulsion polymerization. Transmission electron microscopy (TEM) observations of composite particles show the dependence of particle morphologies with the amount of macromonomer (i.e., mole ratio of macromonomer to BA and molecular weight of macromonomer) in seed latex. The more uniform coverage with the higher amount of macromonomer suggests that graft copolymers decrease the interfacial tension between core and shell layers in the composite particles. Dynamic mechanical analysis of composite latex films indicates the existence of an interphase region between PBA and PMMA. The dynamic mechanical properties of these films are related to the morphology of the composite particles, the arrangement of phases in the films, and the volume of the interphase polymer. © 1997 John Wiley & Sons, Inc.     

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     

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.     

PVC/HfA/MMA/nano-Al(OH)_3复合材料性能的研究

采用丙烯酸六氟丁酯(HfA)和甲基丙烯酸甲酯(MMA)在纳米Al(OH)3(nano-Al(OH)3)颗粒进行表面聚合,使nano-Al(OH)3表面成亲油性,从而与聚氯乙烯(PVC)颗粒的相容性得到提高。在PVC聚合后期加入这种改性剂,纳米粒子包覆在PVC颗粒表面,改性PVC的综合性能得到改善。最佳试验反应条件为:HfA/MMA/nano-Al(OH)3的配比为3∶5∶92,PVC聚合后期加入占改性PVC树脂含量8%的HfA/MMA/nano-Al(OH)3复合材料,制备出的改性PVC树脂混合料的力学性能和耐热抑烟性能均比空白样品大幅提高。     

Highly efficient synthesis of cylindrical polymer brushes with various side chains via click grafting-onto approach

Though much attention has been paid to synthesis of cylindrical polymer brushes, it is still not easy to prepare well-defined brushes by a general approach. Herein, well-defined cylindrical polymer brushes with various side chains were synthesized via grafting-onto approach by CuAAC click chemistry. Narrowly dispersed polymer backbones functionalized with azide groups were obtained by post-modification of poly(glycidyl methacrylate) (PGMA) which was prepared by reversible addition-fragmentation chain transfer (RAFT) mediated radical polymerization. The alkyne-terminated side chains, polystyrene, polyacrylates, polymethacrylates and poly(N-alkyl acrylamide)s, were synthesized by RAFT mediated radical polymerization with alkyne-containing chain transfer agents (CTAs). The CuAAC reactions between the backbone and side chain polymers were conducted with an equivalent feed of alkyne-terminated side chains and azide groups under mild conditions. Influences of reaction conditions and chemical composition of polymer side chains on grafting efficiency and molecular weight distribution of the polymer brushes were investigated. It is demonstrated that the side chains of polystyrene, polyacrylates and poly(N-alkyl acylamide)s were grafted at a density above 85% while that of polymethacrylates decreased to ca. 50%. The polymer brushes synthesized under the optimized reaction conditions had well-defined chemical composition and narrow distribution of molecular weight, and their wormlike morphology was visualized by atomic force microscopy (AFM).     

P(BA-g-MMA)/纳米蒙脱土复合粒子的制备及其增韧PVC的研究

采用种子乳液聚合法制备了纳米蒙脱土(MMT)改性聚丙烯酸丁酯甲基丙烯酸甲酯核壳接枝共聚物P(BA-g-MMA)增韧剂并用于增韧聚氯乙烯（PVC）树脂,分析了MMT含量对共混物力学性能的影响,用X射线衍射仪、扫描电子显微镜观察了蒙脱土的插层和分散效果。结果表明,丙烯酸丁酯(BA)单体在MMT层间发生聚合反应,使MMT层间距由1.25 nm增大至1.5 nm;当P(BA-g-MMA)核壳比(BA∶MMA)为85∶15,100 份（质量份,下同） PVC中加入9份P(BA-g-MMA)时,PVC/P(BA-g-MMA)共混物冲击强度为1106 J/m,是典型的韧性断裂,综合性能好。     

Poly(methyl methacrylate-co-acrylonitrile)

Stable macroradicals of methyl methacrylate were prepared by the azobisisobutyronitrile-initiated polymerization of methyl methacrylate in hexane whose solubility parameter value (δ) differed from that of the macroradical by more than 1.8 hildebrand units and in 1-propanol at temperatures below its theta temperature (84.5°C). The rates of heterogeneous polymerization in hexane and 1-propanol were much faster than that of the homogeneous polymerization in benzene. Stable macroradicals were not obtained in benzene which was a good solvent nor at temperatures above the glass transition temperature (T_t) of the macroradicals. Thus, stable macroradicals of butyl methacrylate (T_g20°C) and and methyl acrylate (T_g3°C) were not obtained at a polymerization temperature of 50°C. Good yields of block copolymers of methyl methacrylate and acrylonitrile were obtained by the addition of acrylonitrile to the methyl methacrylate macroradical in methanol, ethanol, 1-propanol and hexane at 50°C. The rate of formation of the block copolymer decreased in these poor solvents as the differences between the solubility parameter of the solvent and macroradical increased.The block copolymer samples prepared at temperatures of 50°C and above were dissolved in benzene which is a non-solvent for acrylonitrile homopolymer, but is a good solvent for poly(methyl methacrylate) and the block copolymer. The presence of acrylonitrile and methyl methacrylate in the benzene-soluble macromolecule was demonstrated by pyrolysis gas chromatography, infra-red spectroscopy and differential thermal analysis.     

叔碳酸乙烯酯改性醋丙乳液的制备与性能研究

采用半连续种子乳液聚合,以丙烯酸丁酯(BA)、甲基丙烯酸甲酯(MMA)、乙酸乙烯酯(VAc)为主单体,丙烯酸(AA)为功能单体,叔碳酸乙烯酯(VeoVa10)为改性单体,合成了核壳型丙烯酸酯乳液。探讨了聚合温度、乳化剂、引发剂及功能单体与乳液性能的关系。通过单因素实验探讨了乳化剂用量、配比,改性单体用量等与乳液性能的关系。FT-IR和DSC测试结果表明,各单体之间发生了自由基共聚反应,乳液粒子为核壳结构。     

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.     

Miscibility of SAN with polyacrylates and polymethacrylates

Styrene-acrylonitrile copolymers, SAN, are known to be miscible with poly(methyl methacrylate). Based on the presence of a single composition dependent glass transition and lower critical solution temperature behaviour, it is shown that SAN is also miscible with poly(ethyl methacrylate). However, the SAN does not appear to be miscible with other polymethacrylates or polyacrylates.     

Polymer-Impregnated mortars I. Effect of polymer state on mechanical behavior

Mortar specimens were impregnated with methyl methacrylate, n-butyl acrylate, styrene, and crosslinking agents in various combinations. After polymerization of the monomers in situ, studies of mechanical properties such as Young's modulus and compressive strength were made. In one experiment, various ccpolymers of methyl methacrylate and n-butyl acrylate were prepared and tested as a function of temperature. Excellent reinforcement was obtained with any combination of monomers as long as the resulting polymer was at a temperature below its glass transition temperature. This suggests that the modulus of the reinforcing polymer is crucial, glassy behavior being required. The addition of crosslinking agents such as TMPTMA increased the high temperature strength, however.