Development and characterization of reactive extruded PVC/polyacrylate blends

This paper describes a method to obtain polymer blends by the absorption of a liquid solution of monomer, initiator, and a crosslinking agent in suspension type porous poly(vinyl chloride) (PVC) particles, forming a dry blend. These PVC/monomer dry blends are reactively polymerized in a twin‐screw extruder to obtain the in situ polymerization in a melt state of various blends: PVC/poly(methyl methacrylate) (PVC/PMMA), PVC/poly(vinyl acetate) (PVC/PVAc), PVC/poly(butyl acrylate) (PVC/PBA) and PVC/poly(ethylhexyl acrylate) (PVC/PEHA). Physical PVC/PMMA blends were produced, and the properties of those blends are compared to reactive blends of similar compositions. Owing to the high polymerization temperature (180°C), the polymers formed in this reactive polymerization process have low molecular weight. These short polymer chains plasticize the PVC phase reducing the melt viscosity, glass transition and the static modulus. Reactive blends of PVC/PMMA and PVC/PVAc are more compatible than the reactive PVC/PBA and PVC/PEHA blends. Reactive PVC/PMMA and PVC/PVAc blends are transparent, form single phase morphology, have single glass transition temperature (T_g), and show mechanical properties that are not inferior than that of neat PVC. Reactive PVC/PBA and PVC/PEHA blends are incompatible and two discrete phases are observed in each blend. However, those blends exhibit single glass transition owing to low content of the dispersed phase particles, which is probably too low to be detected by dynamic mechanical thermal analysis (DMTA) as a separate T_g value. The reactive PVC/PEHA show exceptional high elongation at break (～90%) owing to energy absorption optimized at this dispersed particle size (0.2–0.8 µm). Copyright © 2005 John Wiley & Sons, Ltd.     

Structure of reactively extruded rigid PVC/PMMA blends

A novel route for producing polymer blends by reactive extrusion is described, starting from poly (vinyl chloride)/methyl methacrylate (PVC/MMA) dry blend and successive polymerization of MMA in an extruder. Small angle X‐ray scattering (SAXS) measurements were applied to study the monomer's mode of penetration into the PVC particles and to characterize the supermolecular structure of the reactive poly(vinyl chloride)/poly(methyl methacrylate) (PVC/PMMA) blends obtained, as compared to the corresponding physical blends of similar composition. These measurements indicate that the monomer molecules can easily penetrate into the PVC sub‐primary particles, separating the PVC chains. Moreover, the increased mobility of the PVC chains enables formation of an ordered lamellar structure, with an average d‐spacing of 4.1 nm. The same characteristic lamellar structure is further detected upon compression molding or extrusion of PVC and PVC/PMMA blends. In this case the mobility of the PVC chains is enabled through thermal energy. Dynamic mechanical thermal analysis (DMTA) and SAXS measurements of reactive and physical PVC/PMMA blends indicate that miscibility occurs between the PVC and PMMA chains. The studied reactive PVC/PMMA blends are found to be miscible, while the physical PVC/PMMA blends are only partially miscible. It can be suggested that the miscible PMMA chains weaken dipole–dipole interactions between the PVC chains, leading to high mobility and resulting in an increased PVC crystallinity degree and decreased PVC glass transition temperature (T_g). These phenomena are shown in the physical PVC/PMMA blends and further emphasized in the reactive PVC/PMMA blends. Copyright © 2005 John Wiley & Sons, Ltd.     

DC Electrical Study of Modified PMMA,PVC and their Blend

Summary: Thin films of high molecular weight PMMA, PVC and their blend were prepared with solution cast method. Further they were modified by adding Camphor Sulphonic Acid (CSA) to them. DSC studies indicate single glass transition temperature (Tg) for unmodified as well as modified blends indicating the miscibility of polymers. FTIR studies show the interaction between CSA-PVC, CSA-PMMA, CSA-(PVC+PMMA) blend. The D.C. electrical study was carried out at various temperatures from room temperature (307 K) to 373 K. After modification the variation of DC conductivity (σ) is found to decrease in PVC and the PVC-PMMA blend whereas it is found to increase in PMMA with rise in temperature.     

Thermal degradation studies in poly(vinyl chloride)/poly(methyl methacrylate) blends

The miscibility, morphology, and thermal properties of poly(vinyl chloride) (PVC) blends with different concentrations of poly(methyl methacylate) (PMMA) have been studied. The interaction between the phases was studied by FTIR and by measuring the glass transition temperature (T_g) of the blends using differential scanning calorimetry. Distribution of the phases at different compositions was studied through scanning electron microscopy. The FTIR and SEM results show little interaction and gross phase separation. The thermogravimetric studies on these blends were carried out under inert atmosphere from ambient to 800 °C at different heating rates varying from 2.5 to 20 °C/min. The thermal decomposition temperatures of the first and second stage of degradation in PVC in the presence of PMMA were higher than the pure. The stabilization effect on PVC was found most significant with 10 wt% PMMA content in the PVC matrix. These results agree with the isothermal degradation studies using dehydrochlorination and UV-vis spectroscopic results carried out on these blends. Using multiple heating rate kinetics the activation energies of the degradation process in PVC and its blends have been reported.     

Transition from miscibility to immiscibility in blends of poly(methyl methacrylate) and styrene-acrylonitrile copolymers with varying copolymer composition: a DSC study

The glass transition and the structural relaxation processes have been studied in blends of poly(methyl methacrylate) (PMMA) and styrene-acrylonitrile (SAN) copolymers with different acrylonitrile (AN) contents. The 50/50 wt.% blend of PMMA with the SAN copolymer containing 30 wt.% of AN is immiscible, while blends with copolymers containing between 13 and 26 wt.% of AN are miscible. Thus the upper limit of miscibility is between 26 and 30 wt.% of AN. The temperature dependence of the relaxation times of the conformational rearrangements of polymer chains around the glass transition have been determined in the blends and pure components by modelling DSC thermograms obtained after different thermal histories in each sample. The slope in the Arrhenius diagram logτ vs 1/T around the glass transition temperature is significantly smaller in the blend which is closer to the upper limit of miscibility than in the other miscible blends in which SAN copolymer contains less AN. The change of slope can be ascribed to a distribution in the glass transition temperatures of the different rearranging regions, reflecting the appearance of a microheterogeneity in the blend that cannot be detected as a double glass transition in the blend.     

The asymmetrical orientational behavior of compatible blends of PMMA and PVC

The orientation and relaxation behavior of compatible blends of poly(methyl methacrylate) (PMMA) and poly(vinyl chloride) (PVC) was investigated. The deformation was performed at 9 K above the glass transition temperature. Based on birefringence and IR-dichroic measurements, it was found that the orientation of PMMA is strongly increased in the blends as compared to pure PMMA at identical draw ratios.The orientation of PVC, on the other hand, is not changed by blending. The results are discussed in terms of friction coefficients and their enhancement by molecular interactions.Dedicated to Prof. E. W. Fischer on the occasion of his 665th birthday     

Miscible blends of polylactide and poly(methyl methacrylate): Morphology,structure, and thermal behavior

The miscibility of polylactic acid (PLA) and atactic poly(methyl methacrylate) (PMMA) blends is investigated as a function of composition. The blends quenched from the melt show the presence of a single glass transition temperature dependent on the composition. The equilibrium melting temperature is determined using the Hoffman‐Weeks method and a depression is observed with increasing content of the PMMA component. The PLA spherulite growth rate and the overall isothermal crystallization rates decrease with increasing the amount of the amorphous component. The increase of the long period value as a function of the PMMA content in the blend is due to the segregation of PMMA component in the amorphous PLA interlamellar regions. The Lauritzen‐Hoffman secondary nucleation theory analysis shows that the segregation of the PMMA in the interlamellar region induces an increase in the surface entropy of folding. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 1168–1177     

FTIR Studies of Doped PMMA - PVC Blend System

The IR spectroscopy study shows miscibility between PMMA-PVC blends due to hydrogen bonding between CO of PMMA and hydrogen from CHCl of PVC. This blend system is doped by Camphor Sulphonic Acid (CSA) in the entire composition range. The doping of CSA in PVC, in PMMA and in PMMA-PVC blends shows changes in FTIR spectra. The interaction between PVC and CSA is through hydrogen bonding between CO of CSA and CHCl of PVC. Doping PMMA with CSA, indicate an interaction between H⁺ ion of CSA and oxygen atoms of CO and  OCH₃ of PMMA. Whereas in PMMA–PVC blend interaction between H⁺ ion of CSA and oxygen atom of CO of PMMA.     

Effect of molecular interactions on the miscibility and structure of polymer blends

The effect of polymer-polymer interactions on the miscibility and macroscopic properties of PVC/PMMA, PVC/PS and PMMA/PS blends were studied in the entire composition range. The miscibility of the components was characterized by the Flory-Huggins interaction parameter or by quantities related to it. Thermal analysis, light transmittance measurements, and scanning electron microscopy were carried out on the blends and their mechanical properties were characterized by tensile tests. Interactions were analyzed by infrared spectroscopy and contact angle measurements. All three polymer pairs form heterogeneous blends, but the strength of molecular interactions is different in them, the highest is in PVC/PMMA system resulting in partial miscibility of the components and beneficial mechanical properties. The structure of these blends depends strongly on composition. A phase inversion can be observed between 0.5 and 0.6 PMMA content accompanied with a significant change in structure and properties. The PVC/PS and the PMMA/PS pairs are immiscible, though the results indicate the partial solubility of the components. The analysis of the surface characteristics of the components and the comparison of quantities derived from them with miscibility as well as with the macroscopic properties of blends revealed that blend properties cannot be predicted in this way, since they are affected by several factors.     

Thermorheological complexity of poly(methyl methacrylate)/poly(vinylidene fluoride) miscible polymer blend: Terminal and segmental levels

Oscillatory shear rheometry data for a miscible blend of 20 wt % poly(vinylidene fluoride) (PVDF) in poly(methyl methacrylate) (PMMA) shows breakdown of time–temperature superposition for this blend. A comparison between glass transition temperature which PMMA chains sense in the blend and effective glass transition temperature of this component indicates that, the Lodge–McLeish model can describe terminal dynamics of PMMA. In addition, terminal dynamics of PVDF chains in the blend is similar to that of its pure state in agreement with the mentioned model. At segmental level, dynamic mechanical thermal analysis of four wholly amorphous blends suggests that cooperativity of molecular motions decreases upon addition of 30 and 40 wt % PVDF to PMMA. This behavior has been confirmed via calculation of degree of fragility which presumably is attributed to strong tendency of PVDF chains to self‐association rather than inter‐association with PMMA chains according to the FTIR results. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2860–2870, 2007     

Investigating the effect of nanolayered silicates on blend segmental dynamics and minor component relaxation behavior in poly(ethylene oxide)/poly(methyl methacrylate) miscible blends

Polymer–silicate nanocomposites based on poly (ethylene oxide), PEO, poly(methyl methacrylate), PMMA, and sodium montmorillonite clay were fabricated and characterized to investigate the effect of nanolayered silicates on segmental dynamics of PEO/PMMA blends. X‐ray results indicate the formation of an exfoliated morphology in the nanocomposites. At low silicate contents, an enhancement in segmental dynamics of blend nanocomposites and also PEO, minor component in blend, is observed at temperature region below blend glass transition. This result can be attributed to the improvement of the confinement effect of rigid PMMA matrix on the PEO chains by introducing a low amount of layered silicates. On the other hand, at high silicate contents, an enhancement in segmental dynamics of blend nanocomposites and PEO is observed at temperature region above blend glass transition. This behavior could be interpreted based on the reduction of monomeric friction between two polymer components, which can facilitate segmental motions of blend components in nanocomposite systems. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011     

Proton NMR investigation of the local dynamics of PEO in PEO/PMMA blends

Longitudinal relaxation of proton magnetisation was used to characterize the molecular motions of PEO chains in compatible PEO (hydrogenated)/PMMA (deuterated) blends. Both the temperature and the PEO concentration, Φ, were varied. A maximum in the spin–lattice relaxation rate was observed and its properties were analyzed as a function of Φ. For Φ ≤ 0.50, the maximum is observed below the glass transition temperature of the blend; this shows that PEO chains dispersed in a matrix of PMMA remain highly mobile on a local scale even below T_g(Φ). A frequency–temperature correspondence procedure, applied to the measurements performed at two Larmor frequencies, 32 and 60 MHz, leads to a characteristic correlation time for PEO molecular motions. Its temperature dependence obeys a WLF free volume relation above the glass transition of the blends. The PEO free volume fraction and its thermal expansion are strongly reduced by the presence of the PMMA chains. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 1095–1105, 1997     

PVC/ACR共混物微观结构与性能

本文研究了聚氯乙烯/丙烯酸酯类共聚物(PVC/ACR)共混物的应力-应变行为和冲击强度对ACR 用量的依赖关系。ACR对 PVC有良好的增韧作用,提高了PVC抗冲击性能。考察了三盐基性硫酸铅和硬脂酸钡-硬脂酸镉稳定剂对共混体系的影响,实验结果说明不同的热稳定体系对ACR改性PVC的效果有差别。动态力学性能测定结果表明PVC/ACR共混物存在两个玻璃化转变温度,证明PVC与ACR不相容性;而两个转变温度随共混物组成改变而变化,说明PVC与ACR之间存在着相互作用,PVC/ACR为部分相容体系。通过透射电子显微镜观察PVC/ACR共混物的微观结构形态表明:PVC与 ACR为两相体系,ACR呈粒状分布在PVC连续相中。但是,采用硬脂酸钡-硬脂酸镉稳定体系时,随着ACR用量增加,ACR的分散形态由粒状分散逐渐形成网络结构形态,与此相对应的共混物具有更好的抗冲击性能。     

Blends of poly(methyl methacrylate) (PMMA) with PMMA ionomers: Mechanical properties

Rigid–rigid blends made of ionomer and ionomer precursor polymer, based on poly(methyl methacrylate) (PMMA), have been investigated. Two series of blends have been prepared for studying mechanical properties. In one series, dynamic mechanical properties were determined over a wide range of temperatures. As the weight fraction of the ionomer was increased, there was a modest increase of modulus at ambient temperature and a very large increase in the rubbery modulus at elevated temperatures above the glass transition temperature of PMMA. In a second series of tests, tensile stress–strain measurements, made at an ambient temperature, were carried out over a wide range of blend compositions. For all blends tested, the mechanical properties exhibited a synergistic enhancement, i.e., average values of modulus, strength and fracture energy were all higher than expected based on the rule of mixtures. Measurements of fracture toughness also exhibited synergy, with a maximum value, higher than the value of either blend component, being attained in blends containing about 30 wt % of the PMMA ionomer. These results are interpreted in terms of a higher resistance to fracture of the more chain-entangled ionomer phase and good interfacial adhesion between the two components of the blend. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 1235–1245, 1998     

Die spezifische Wärme des Polyvinylchlorids

Zusammenfassung Die spezifische Wärme verschiedener handelsüblicher Polyvinylchlorid-Sorten (Suspensions- und Emulsions-PVC, schlagfestes PVC und ein Vinylchlorid-Vinylacetat-Copolymerisat) wurde im Temperaturbereich 20 (bzw. –50) bis 140 °C mit einem adiabatischen Kalorimeter gemessen. Besondere Aufmerksamkeit wurde dem Einfluß der thermischen Vorgeschichte gewidmet. Messungen an getemperten Proben ergaben — in Übereinstimmung mit den Ergebnissen anderer Autoren —einfache Kurvenzüge mit einem Steilanstieg der spezifischen Wärme im Einfriergebiet. Untersuchungen an abgeschreckten Proben ließen zu Beginn des Einfrierbereiches Minima der spezifischen Wärme infolge Enthalpierelaxation erkennen. Oberhalb des Einfrierbereichs zeigten sich Kristallisationserscheinungen mit Wärmetönungen von etwa –1,3 cal/g (exotherm). Hieraus wurde der kristalline Anteil des Polyvinylchlorids zu rund 3% abgeschätzt. Der Schmelzpunkt der PVC-Kristallite wurde differentialthermoanalytisch zu 156 bzw. 170 °C gefunden. Das schlagfeste PVC ließ das Schmelzen einer Spur Polyäthylen zwischen 102 und 125 °C erkennen. Die kalorimetrisch bestimmten Einfriertemperaturen stimmen mit dilatometrisch gemessenen — gleiche thermische Vorbehandlung vorausgesetzt — überein.

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Summary The specific heat of some commercially available samples of polyvinyl chloride (suspension PVC, emulsion PVC, high impact PVC, and a copolymerisate of vinylchloride and vinylacetate) was measured in the temperature range from 20 (or –50) to 140 °C, using an adiabatic calorimeter. Special attention was paid to the influence of thermal history of the samples. Investigations of annealed samples gave simple curves with a steep slope in the glass transition range, in agreement with the results of other authors. Measurements with samples quenched in ice water showed specific heat curves with a minimum at the beginning of the glass transition range caused by enthalpy relaxation. Above the glass transition range crystallization occurred accompanied by heat effects of about –1,3 cal/g (exothermal). From this the fraction of crystalline PVC was estimated to be about 3%. The melting point of the PVC crystallites as determined by differential thermal analysis was 156 or 170 °C. With high impact PVC the melting of traces of polyethylene was observed between 102 and 125 °C. The glass transition temperatures as determined by calorimetry agreed with those determined by dilatometric measurements, provided thermal pretreatment being equal in both cases.

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Mit 14 Abbildungen und 5 Tabellen     

共混方法对聚氯乙烯/聚丙撑碳酸酯相容性影响

本文分别用溶液法和熔融法制得聚氯乙烯（PVC）与聚丙撑碳酸酯（PPC）共混试样，用DSC证明PVC／PPC共混物不相容，但它们不相容的程度受分子量、共混比例等因素的影响，并根据玻璃化转变温度（Tg）计算出溶液共混试样PPC富相中PVC的重量百分含量。NBR／PPC弹性体作偶联剂对PVC／PPC共混体系具有较好的增容作用，共混物中PPC的用量及分子量对共混体系性能有一定的影响。     

Surface segregation of poly(2-methoxyethyl acrylate) in a mixture with poly(methyl methacrylate)

Poly(2-methoxyethyl acrylate) (PMEA) exhibits excellent blood compatibility. To understand why such a surface functionality exists, the surface of PMEA should be characterized in detail, structurally and dynamically, under not only ambient conditions, but also in water. However, a thin film of PMEA supported on a solid substrate can be easily broken, namely it is dewetted. Our strategy to overcome this difficulty is to mix PMEA with poly(methyl methacrylate) (PMMA). Differential scanning calorimetry and cloud point measurements revealed that the PMEA/PMMA blend has a phase diagram with a lower critical solution temperature. The blend surface was also characterized by X-ray photoelectron spectroscopy in conjunction with microscopic observations. Although PMEA is preferentially segregated over PMMA at the blend surface due to its lower surface free energy, the extent of segregation in the as-prepared films was not sufficient to cover the surface. Annealing the blend film at an appropriate temperature, higher than the glass transition temperature and lower than the phase-separation temperature of the blend, enabled us to prepare a stable and flat surface that was perfectly covered with PMEA.     

Control of phase separation behavior of PC/PMMA blends and their application to the gas separation membranes

Gas transport and thermodynamic properties for the blends of polycarbonate (PC) and polymethylmethacrylate (PMMA) were studied. To explore glass transition temperatures of blends and their phase separation temperatures due to a lower critical solution temperature, LCST, a type of phase boundary, transparent blend films that are miscible and do not contain solvent-induced PC crystals were prepared by controlling molecular weights of each component. The average value of interaction energy densities between PC and PMMA obtained from the phase boundaries and the equation of a state theory based on the lattice fluid model was 0.04 cal/cm³. This result confirmed that miscibility of PC and PMMA blends at equilibrium depends upon the molecular weights of components. Gas transport properties of miscible blends and immiscible blends having the same chemical components and composition but a difference in morphology were examined at 35°C and 1 atm for the gases N₂ and O₂. Permeability and apparent diffusion coefficients were ranked in the order of the immiscible blend having a domain–matrix structure > the immiscible blend having an interconnected structure > the miscible blend. These results might be related to the differences in the local chain motions that depend on the intermolecular mixing level. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 2950–2959, 1999     

Thermal and mechanical behavior of amorphous and semi-crystalline poly(vinylidene fluoride)/poly(methyl methacrylate) blends

Various PVDF/PMMA (poly(vinylidene fluoride)/poly(methyl methacrylate)) blends were selected for mechanical testing in compression. At low PVDF content (less than 50/50 w/w), the blends remain amorphous and PVDF and PMMA are fully miscible. In PVDF-richer blends, PVDF crystallizes in part, leading to a PMMA-enriched homogeneous amorphous phase. In this study, the degree of crystallinity was set at equilibrium by appropriate annealing of the samples before testing. Mechanical analysis was focused on the low deformation range, and especially on the yield region. Depending on the test temperature and blend composition, three types of response were identified, depending on whether plastic deformation is influenced: 1) by the PMMA secondary relaxation motions, 2) by the PVDF/PMMA glass transition motions, or 3) by the crystallite-constrained PVDF chains.     

Investigation at the chain segmental level of the miscibility of poly(vinyl chloride)/atactic poly(methyl methacrylate) blends

We employed high‐resolution ¹³C cross‐polarization/magic‐angle‐spinning/dipolar‐decoupling NMR spectroscopy to investigate the miscibility and phase behavior of poly(vinyl chloride) (PVC)/poly(methyl methacrylate) (PMMA) blends. The spin–lattice relaxation times of protons in both the laboratory and rotating frames [T₁(H) and T_1ρ(H), respectively] were indirectly measured through ¹³C resonances. The T₁(H) results indicate that the blends are homogeneous, at least on a scale of 200–300 Å, confirming the miscibility of the system from a differential scanning calorimetry study in terms of the replacement of the glass‐transition‐temperature feature. The single decay and composition‐dependent T_1ρ(H) values for each blend further demonstrate that the spin diffusion among all protons in the blends averages out the whole relaxation process; therefore, the blends are homogeneous on a scale of 18–20 Å. The microcrystallinity of PVC disappears upon blending with PMMA, indicating intimate mixing of the two polymers. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2390–2396, 2001