In this work the effect of melt mixing condition and of a trans‐esterification catalyst on miscibility of poly(methyl methacrylate) (PMMA)/polycarbonate of bisphenol A (PC) blends is studied. In particular, at high temperature chemical reactions between PMMA and PC phases can take place; these strongly change the compatibility in the blend and materials having single Tg can be obtained. FT‐IR analyses, coupled with solvent extraction, suggest that a grafting reaction of PC on PMMA is involved. SEC and DSC data are consistent with spectroscopic results, and some decrement of the molar weight distribution (MWD) of PC phase is observed. On the other hand, the presence of a fraction of modified material having higher MWD of starting PMMA is also noticed. The single Tg characteristic of some materials has been confirmed by experimental data of structural relaxation performed by differential scanning calorimetry (DSC). These materials showed optical clarity and the morphological analysis performed by scanning electron microscopy (SEM) confirm the homogeneity of these materials.

Summary: The synthesis and the properties of block copolymers based on PPO and PC segments are reported. Copolymers that have a multi‐block structure are synthesized by a polycondensation reaction that employs oligomeric PPO and PC diol terminated with phosgene or bischloroformate of bisphenol A. In the reaction scheme two steps are involved: first, the reaction of one of the oligomeric diols (PPO or PC) with the bischloroformate or phosgene; second, the oligomeric bischloroformate is reacted with the other diol. The molecular characteristics of the prepared samples are studied by SEC, 1H and 13C NMR, and FT‐IR spectroscopy. The thermal and rheological properties and the thermal stability have also been investigated by means of DSC, rotational rheometry, and TGA, respectively. Polymers that have a single glass transition temperature are obtained if low‐molecular‐weight segments are used. From a rheological point of view, these materials show a remarkably lower melt viscosity compared with a PPO homopolymer that has a comparable average molecular weight.

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ABSTRACT:The aim of this work was the development of materials to be used in the field of gas sensing for the detection of organic vapors. Conductive sensors were prepared with carbon black filled blends of poly(vinyl chloride) and diol-terminated poly(⑀-caprolactone), an oligomeric plasticizer. For comparison, blends with di(2-ethylhexyl)-phthalate, a traditional low-molecular-weight plasticizer, were also prepared. All sensors were tested upon exposure to different organic vapors. In general, the plasticizer content affected the response rates of the sensors, and a linear variation of the relative resistance with the analyte concentration was observed.

Block-copolymers containing poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and polycarbonate of bisphenol A (PC) segments were employed as compatibilizers in polystyrene (PS)/PC blends. Block-copolymers were prepared starting from oligomeric diols-terminated PPO and PC. The poly(phenylene ethers) was obtained by oxidative coupling of 2,6-dimethyl-phenol in presence of tetramethyl bisphenol A. The copolymers were obtained with a chain extension reaction between the starting oligomers using bischloroformate of bisphenol A or phosgene as coupling agent. PS/PC blends, cast from chloroform solutions or mixed by melt, were studied by differential scanning calorimeter (DSC), dynamic-mechanical thermal analysis (DMTA), and optical microscopy (OP). The thermal and morphological analyses showed a clear compatibilization effect between PS and PC, if PPO-PC copolymer is added when blending is performed in the melt; in addition, also mechanical properties are increased when compared with blends without PPO-PC.