Effect of tacticity of poly(methyl methacrylate) on the miscibility with poly(vinyl acetate)

The results of the miscibility between the chemically similar polymers poly(methyl methacrylate) (PMMA) and poly(vinyl acetate) (PVAc) published so far show inconsistent statements concerning miscibility. The problems may be due to differences in molecular weights, tacticity, and preparation methods of the polymers. This investigation was carried out by using either chloroform or tetrahydrofuran (THF) as solvent to prepare the blends, because to our knowledge, nobody has reported any tacticity effect of PMMA on the miscibility with PVAc. Therefore, in this article, different tactic PMMAs were used to mix with PVAc and their miscibility was studied calorimetrically. The results showed little effect of solvent and tacticity. PMMA and PVAc were determined to be almost completely immiscible because of the observation of two T_g's. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 35–39, 2004     

Effect of tacticity of poly(methyl methacrylate) on the miscibility with poly(vinyl pyrrolidone)

Isotactic, atactic, and syndiotactic poly(methyl methacrylates) (PMMA) (designated iPMMA, aPMMA, and sPMMA) with approximately the same molecular weight were mixed separately with poly(vinyl pyrrolidone) (PVP) primarily in chloroform to make three polymer blend systems. Differential scanning calorimetry (DSC) was used to study the miscibility of these blends. The results showed that the tacticity of PMMA has a definite impact on its miscibility with PVP. The aPMMA/PVP and sPMMA/PVP blends were found to be miscible because all the prepared films showed composition-dependent glass-transition temperatures (T_g). The glass-transition temperatures of the aPMMA/PVP blends are equal to or lower than weight average and can be qualitatively described by the Gordon–Taylor equation. The glass-transition temperatures of the other miscible blends (i.e., sPMMA/PVP blends) are mostly higher than weight average and can be approximately fitted by the simplified Kwei equation. The iPMMA/PVP blends were found to be immiscible or partially miscible based on the observation of two glass-transition temperatures. The immiscibility is probably attributable to a stronger interaction among isotactic MMA segments because its ordination and molecular packing contribute to form a rigid domain. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3190–3197, 2001     

Effect of tacticity on the transition behaviour of poly(methyl methacrylate)/poly(vinyl chloride) blends. Thermally stimulated depolarization study

The transition behaviour of blends of poly(vinyl chloride) (PVC) and poly(methyl methacrylate) isotactic (i-PMMA) and syndiotactic (s-PMMA) was determined in the temperature range ?150°C to +130°C by the thermally stimulated depolarization currents method (TSDC). The evolution of the current spectra was analysed as a function of blend composition. From the variation of properties of the peaks (presence or not of two T_g peaks, shifting or not of their positions, existence or not of interfacial components, regular or complex variation of the peak amplitudes ...), it was concluded that i-PMMA and PVC form an incompatible system over the entire concentration range while in s-PMMA/PVC blends, some compatibility probably exists but only for concentrations in s-PMMA not higher than 10 wt%. By referring to literature data, this value is much smaller than the compatibility range found from d.s.c. and mechanical measurements but is close to that determined from optical and electronic spectroscopy methods. These results emphasize the important role played by the type of method used to find out compatibility of a given polymer pair and show that the TSDC technique may be particularly useful for studying the interfacial phenomena associated with phase separation owing to its exceptional ability for easily detecting Maxwell-Wagner-Sillars polarization generated by the trapping of charge carriers at phase boundaries.     

Effect of the tacticity of poly(methyl methacrylate) on the phase diagram of its ternary blends

Previously, isotactic and atactic poly(methyl methacrylates) (PMMAs) were found to be miscible with poly(vinyl phenol) (PVPh) and poly(hydroxy ether of bisphenol‐A) (phenoxy) because all the prepared films were transparent and showed composition‐dependent glass transition temperatures (T_g's). However, syndiotactic PMMA was immiscible with PVPh because most of the cast films had two T_g's. On the contrary, syndiotactic PMMA was still miscible with phenoxy. According to our preliminary results, PVPh and phenoxy are not miscible. Also to our knowledge, nobody has reported any results concerning the effect of the tacticity of PMMA on its ternary blend containing PVPh and phenoxy. The miscibility of a ternary blend consisting of PVPh, phenoxy, and tactic PMMA was thus investigated and reported in this article. Calorimetry was used as the principal tool to study miscibility. An approximate phase diagram of the ternary blends containing different tactic PMMA was established, probably for the first time, based on differential scanning calorimetry data. Immiscibility was found in most of the studied ternaries but a slight difference due to the effect of tacticity of PMMA was definitely observed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2720–2726, 2002     

Study of the solvent effect on miscibility between poly(vinyl chloride) and poly(methyl methacrylate) in the solution state – viscometric measurements

In this work, the solvent effect on the miscibility between poly(vinyl chloride) (PVC) and poly(methyl methacrylate) (PMMA) in ternary polymer solutions was examined by the viscometric method. In these systems, we could understand that the used solvents, tetrahydrofuran (THF) or N,N‐dimethylformamide (DMF), mainly affect the interaction between PVC and PMMA, while prompting various miscible properties. In PVC/PMMA/THF solution, THF is a near θ‐solvent and a poor solvent for PVC and PMMA, respectively. The mixing of the tighter PMMA coils and more extended PVC coils in THF may cause the sea–island heterogeneous structure below the weight fraction of PMMA in the polymer mixture w_PMMA = 0.7, resulting in immiscible PVC/PMMA mixtures. At w_PMMA ≥ 0.7, the PVC/PMMA mixtures are relatively miscible, giving homogeneous polymer solutions. It means that the miscibility between PVC and PMMA depends on the composition of polymer mixture. However, due to the similar affinity of DMF to PVC and PMMA, PVC/PMMA/DMF solutions exhibit high miscibility between PVC and PMMA at about w_PMMA = 0.5. © 2000 Society of Chemical Industry     

Effect of tacticity of poly(methyl methacrylate) on the miscibility with poly(styrene‐co‐acrylonitrile)

Isotactic, atactic, and syndiotactic poly(methyl methacrylates) (PMMAs) (designated as iPMMA, aPMMA, and sPMMA) with approximately the same molecular weight were mixed separately with poly(styrene‐co‐acrylonitrile) (abbreviated as PSAN) containing 25 wt % of acrylonitrile in tetrahydrofuran to make three polymer blend systems. Differential scanning calorimetry (DSC) was used to study the miscibility of these blends. The results showed that the tacticity of PMMA has a definite impact on its miscibility with PSAN. The aPMMA/PSAN and sPMMA/PSAN blends were found to be miscible because all the prepared films were transparent and showed composition dependent glass transition temperatures (T_gs). The glass transition temperatures of the two miscible blends were fitted well by the Fox equation, and no broadening of the glass transition regions was observed. The iPMMA/PSAN blends were found to be immiscible, because most of the cast films were translucent and had two glass transition temperatures. Through the use of a simple binary interaction model, the following comments can be drawn. The isotactic MMA segments seemed to interact differently with styrene and with acrylonitrile segments from atactic or syndiotactic MMA segments. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2894–2899, 1999     

Influence of tacticity of poly(methyl methacrylate) on the compatibility with poly(vinyl phenol)

Isotactic, atactic, and syndiotactic poly(methyl methacrylate) (PMMA) were mixed with poly(vinyl phenol) (PVPh) separately in tetrahydrofuran to make three polymer blend systems. Differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy were used to study the miscibility of these blends. Isotactic PMMA was found to be more miscible with PVPh than atactic or syndiotactic PMMA. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1773–1780, 1997     

Comparison of the phase behaviour of the liquid-crystalline polymer/poly(methyl methacrylate) and poly(vinyl acetate)/poly(methyl methacrylate) blends

The phase behaviour of blends of a liquid-crystalline polymer (LCP) and poly(methyl methacrylate) (PMMA), as well as the phase state of blends of PMMA and poly(vinyl acetate) (PVA) has been investigated using light scattering and phase-contrast optical microscopy. The blends of LCP and PMMA have been obtained by coagulation from ternary solutions. The cloud point curves were determined. It was established that both pairs demix upon heating, ie have an LCST. In the region of intermediate composition, the phase separation proceeds according to a spinodal mechanism; however for LCP/PMMA blends, the decomposition proceeds according to a non-linear regime from the very onset. In the region of small amounts of LCP, the phase separation follows a mechanism of nucleation and growth. For PMMA/PVA blends, the spinodal decomposition proceeds according to a linear regime, in spite of the molecular mobility that PVA chains develop at lower temperatures. Only after prolonged heat treatment does the process transit to a non-linear regime. The data show a similarity between the phase behaviour of blends of liquid-crystalline and of flexible amorphous polymers. The distinction consists of the absence of a linear regime of decomposition for LCP-PMMA blends. © 1999 Society of Chemical Industry     

The effect of layered double hydroxides dispersion on thermal and mechanical properties of poly(vinyl chloride)/poly(methyl methacrylate) blends

Poly(vinyl chloride) (PVC)/layered double hydroxide (LDH) composites and PVC/poly(methyl methacrylate) (PMMA)/LDH composites were prepared via solution intercalation into PVC using both unmodified and organo‐modified LDHs and variable‐molecular‐weight PMMA as additional components. The LDH dispersion was investigated using X‐ray diffraction analysis and electron microscopy in scanning and transmission modes. Spotlight fourier transform infrared (FTIR) chemical imaging analysis was also used to obtain a deeper insight into the dispersion of polymer phases and LDH segregation. Thermal properties were determined using thermogravimetric analysis and differential scanning calorimetry; moreover, a preliminary investigation of mechanical properties in tensile mode and evaluation of the Vicat softening temperature were carried out. The morphological analysis of PVC/LDH and PVC/PMMA/LDH composites evidenced in both cases the presence of disordered micro‐aggregates with loss of the LDH crystallographic symmetry depending on the amount and molecular weight of PMMA. In particular, in the case of PVC/PMMA/LDH composites, the FTIR imaging analysis showed that PMMA mostly segregated in the LDH phase. However, even if the degree of LDH dispersion was not elevated (micro‐aggregates with disordered structures and size ranging from 0.5 up to 11 µm were evidenced), thermal stability and mechanical properties of the composites were improved with a synergic effect of PMMA and LDH. © 2013 Society of Chemical Industry     

Phase behavior and properties of poly(methyl methacrylate)/poly(vinyl acetate) blends prepared via in situ polymerization

Polymer blends composed of poly(methyl methacrylate) (PMMA) and poly(vinyl acetate) (PVAc) were prepared via radical-initiated polymerization of methyl methacrylate (MMA) in the presence of PVAc. Differential scanning calorimetry and dynamic mechanical analysis were employed to investigate the miscibility and phase behavior of the blends. The PMMA/PVAc blends of in situ polymerization were found to be phase separated and exhibited a two-phase structure, although some chain transferring reaction between the components occurred. The phase separation resulted from the solvent effect of MMA during the in situ polymerization, which was confirmed by the investigation of phase behavior based on solution cast blending. Solubility analysis of the polymerized blends indicated that some chain transferring reaction between the components occurred during the polymerization. An abrupt increase in gel content from 21.2 to 72.4 wt % was observed when the inclusion of PVAc increased from 30 to 40 wt %, and the gel component consisted of the component polymers as shown by infrared spectroscopy studies. The thermogravimetric analysis study indicated that the inclusion of a small amount of PVAc gives rise to a marked stabilization effect on the thermal stability. The PMMA/PVAc blends exhibited increased notched impact properties with the inclusion of 5 wt % PVAc. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 675–684, 1998     

Physical Properties of Plasticized Poly(vinyl chloride) Blended with Poly(methyl methacrylate) Nanoparticles Synthesized by Differential Microemulsion Polymerization

In this work, poly(methyl methacrylate) (PMMA) nanoparticles synthesized by differential micro emulsion polymerization were used to improve the physical properties of plasticized poly(vinyl chloride) (PVC). PVC, plasticizer (40 phr), heat stabilizer (2 phr), and lubricant (0.2 phr) were melt-mixed with varied amount of the PMMA nanoparticles (3, 5, 7, and 9 phr) on a two-roll mill, followed by compression molding. The results showed that the tensile strength, Young's modulus, tear strength, and thermal stability were improved, but the elongation at break deteriorated with increased PMMA content. Moreover, the flammability of the plasticized PVC was not improved by the PMMA nanoparticles.     

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     

Blends of plasticized poly(vinyl chloride) and waste flexible poly(vinyl chloride) with waste nitrile rubber powder

Blends of poly(vinyl chloride) (PVC) with varying contents of plasticizer and finely ground powder of waste nitrile rubber rollers were prepared over a wide range of rubber contents through high‐temperature blending. The effects of rubber and plasticizer (dioctyl phthalate) content on the tensile strength, percentage elongation, impact properties, hardness, abrasion resistance, flexural crack resistance, limiting oxygen index (LOI), electrical properties, and breakdown voltage were studied. The percentage elongation, flexural crack resistance, and impact strength of blends increased considerably over those of PVC. The waste rubber had a plasticizing effect. Blends of waste plasticized PVC and waste nitrile rubber showed promising properties. The electrical properties and LOI decreased with increasing rubber and plasticizer content. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1552–1558, 2004     

Thermal degradation behavior of poly(vinyl chloride) in the presence of poly(glycidyl methacrylate)

The thermal degradation behavior of poly(vinyl chloride) (PVC) in presence of poly(glycidyl methacrylate) (PGMA) has been studied using continuous potentiometric determination of the evolved HCl gas from the degradation process from one hand and by evaluating the extent of discoloration of the degraded samples from the other. The efficiency of blending PGMA with dibasic lead carbonate (DBLC) conventional thermal stabilizer has also been investigated. A probable radical mechanism for the effect of PGMA on the thermal stabilization of PVC has been suggested based on data reported by FTIR and elemental analyses. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Crystallization behavior and hydrophilicity of poly(vinylidene fluoride)/poly(methyl methacrylate)/poly(vinyl pyrrolidone) ternary blends

Ternary blends composed of matrix polymer poly(vinylidene fluoride) (PVDF) with different proportions of poly(methyl methacrylate) (PMMA)/poly(vinyl pyrrolidone) (PVP) blends were prepared by melt mixing. The miscibility, crystallization behavior, mechanical properties and hydrophilicity of the ternary blends have been investigated. The high compatibility of PVDF/PMMA/PVP ternary blends is induced by strong interactions between the carbonyl groups of the PMMA/PVP blend and the CF₂ or CH₂ group of PVDF. According to the Fourier transform infrared and wide‐angle X‐ray difffraction analyses, the introduction of PMMA does not change the crystalline state (i.e. α phase) of PVDF. By contrast, the addition of PVP in the blends favors the transformation of the crystalline state of PVDF from non‐polar α to polar β phase. Moreover, the crystallinity of the PVDF/PMMA/PVP ternary blends also decreases compared with neat PVDF. Through mechanical analysis, the elongation at break of the blends significantly increases to more than six times that of neat PVDF. This confirms that the addition of the PMMA/PVP blend enhances the toughness of PVDF. Besides, the hydrophilicity of PVDF is remarkably improved by blending with PMMA/PVP; in particular when the content of PVP reaches 30 wt%, the water contact angle displays its lowest value which decreased from 91.4° to 51.0°. Copyright © 2011 Society of Chemical Industry     

聚甲基丙烯酸甲酯包覆纳米CaCO3改性聚氯乙烯研究

研究了聚甲基丙烯酸甲酯(PMMA)包覆纳米CaCO3复合粒子填充聚氯乙烯(PVC)复合材料的加工塑化和力学性能，并与未改性纳米CaCO3的改性效果进行比较。结果发现，填充纳米CaCO3使PVC平衡扭矩和平衡熔融温度均会有所提高，填充未改性碳酸钙增加更大，填充PMMA包覆CaCO3使材料冲击性能提高的幅度大于填充未改性纳米CaCO3，而拉伸强度下降幅度较小。当PMMA包覆CaCO3填充量为8％时缺口冲击强度增加到未改性PVC的194％。冲击缺口断面形态分析表明，采用PMMA包覆CaCO3时，纳米CaCO3在PVC基体中分散均匀、团聚少。     

Properties of mineral filled poly(lactic acid)/poly(methyl methacrylate) blend

This study examines the influence of three different minerals, that is, clay, calcium carbonate, and quartz on the physical, thermal, and mechanical properties of poly(lactic acid) (PLA)/poly(methyl methacrylate) blend. Rheological behavior and phase structure were initially studied by small-amplitude oscillatory shear rheology. Clay- and quartz-filled materials presented an increase in viscosity at low frequency associated with the presence of a yield stress. However, this behavior was not observed for calcium carbonate filled materials due to a matrix degradation effect. To elucidate this aspect, thermal stability and thermal properties were examined by thermogravimetric analysis and differential scanning calorimetry, showing that calcium carbonate promotes degradation of the PLA phase. No nucleating effect was observed in the presence of the minerals. Dynamical mechanical analysis and mechanical characterization revealed an increase of the overall softening temperature and, a reinforcing effect for clay- and quartz-based composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46927.     

Solvent effects on the miscibility of poly(methyl methacrylate)/poly(bisphenol a carbonate) blends

Blends of atactic or syndiotactic poly(methyl methacrylate) (designated as aPMMA or sPMMA) and poly(bisphenol A carbonate) (PC) were prepared from solution casting. Tetrahydrofuran (THF) and chloroform were used as solvent. Experimental results indicated that the as‐cast blends from THF were quite different from the chloroform‐cast ones. After film preparation, THF‐cast blends did not show any visible phase separation. However, chloroform‐cast blends formed a phase‐separated structure. The as‐cast PC from either solvent was not completely amorphous, and had a melting point at 239–242°C, indicating a certain degree of crystallinity. In contrast, the quenched samples of aPMMA/PC blends prepared from the two solvents behaved virtually the same. They both showed aPMMA dissolves better in PC, but PC solubility in aPMMA is very little. Using sPMMA instead of aPMMA to blend with PC, different results were obtained. The quenched sPMMA/PC blends cast from THF showed only one T_g. However, immiscibility (i.e., two T_gs) was found in the same blend system when cast from chloroform. THF was believed to cause the observation of single T_g due to the following kinetic reason. sPMMA and PC were still trapped together even after THF removal in a homogeneous, but nonequilibrium state below the glass transition. Therefore, the quenched sPMMA/PC blends were not truly thermodynamically miscible. From the results of aPMMA or sPMMA with PC, increasing syndiotacticity seemed to improve the miscibility between PMMA and PC. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2842–2850, 2001     

Behavior of flexible poly(vinyl chloride)/poly(hydroxybutyrate valerate) blends

Blends of flexible poly(vinyl chloride) (PVC) and a poly(hydroxybutyrate valerate) (PHBV) copolymer were prepared and characterized with different techniques. The tensile strength of PVC did not show a marked reduction at PHBV concentrations up to 50 phr, despite a lack of miscibility between the two polymers. The crystallization of the PHBV copolymer was markedly hindered by the presence of PVC, as calorimetric results revealed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Dynamical study on the late stage of demixing in poly(methyl methacrylate) and poly(vinyl acetate) blends

A dynamical study was made on demixing of an immiscible polymer blend, whose specimens were prepared by solvent casting and had very finely phase separated structures in the initial stage of the demixing. Light scattering experiments showed the applicability of a scaling rule to the later stage of the growth of phase separation structures. The demixing can be described by a scaling theory proposed by Furukawa.