Formation of Polyurethane Film Containing Silicone Polymer with Silanol Residue

The silicone polymers containing a silanol residue were synthesized from silica gel, while the polyurethanes (PUs) bearing a carboxyl moiety were prepared using 2,2-bis(hydroxymethyl)propionic acid (BHMPA) as one of the diol components. The fabrication of the PU films was carried out using these two polymers, then the tensile and thermal properties were investigated. Both the amounts of the carboxyl side groups of the PU chain and the residual silanol of the silicone polymer significantly affected the mechanical property of the film, in addition, the incorporation of 3-aminopropyltrimethoxysilane (APTMS) was quite effective for enhancing the elastic modulus (E). As a result, the film prepared from the polyurethane containing the BHMPA unit with a combination of APTMS and the silicone polymer, having a proper amount of silanol groups, showed the highest effect (E = 5.36 N/mm2), while that observed for the film prepared without using BHMPA and a silicone polymer was 2.10 N/mm2. An acid-base interaction between the carboxyl moiety of the PU and amino group of APTMS occurred, while the formation of the siloxane linkage through the silylation reaction between the trimethoxysilyl group of APTMS and silanol also took place

Effective Synthesis of Poly(2,6-Dimethyl-1,4-Phenylene Oxide) Derivatives by Oxidative Coupling Copolymerization of Alkoxyphenols with Copper(II) Catalyst

The oxidative coupling copolymerization between 2,6-dimethylphenol (DMP) and phenols having various alkoxy groups, such as methyoxy (MOP), ethoxy, benzyloxy, butoxy, and 2-hydroxyethoxy groups, was carried out using a copper(II) catalyst under an O2 atmosphere. The copolymerizations with alkoxyphenols effectively proceeded, and the unit ratios of the obtained copolymers were in good agreement with those in the feed. The coupling regioselectivity, such as oxyphenylene (CO) and phenylene (CC), of the alkoxyphenol unit constructed during the copolymerization was also estimated by the 1H NMR analysis of the acetylated polymer. As an example, the copolymer with the unit ratios of DMP:p-MOP = 50:50 and CO:CC = 67:33, was obtained in 71% yield during the copolymerization with p-MOP (feed ratio, 50:50) in a mixed solvent of CH2Cl2 and methanol (7/1 (v/v)) for 24 h. The solubility and thermal property of the obtained copolymers were significantly affected by the structure of alkoxyphenol unit

Stereospecific Anionic Polymerization of α-(Hydroxymethyl)acrylate with Protective Group

Anionic polymerizations of hydroxyl-protected α-(hydroxymethyl)acrylates were investigated. The methyl ester with methoxymethyl (1-MOM) and allyl (1-allyl) protecting groups were polymerized by isopropyl α-lithioisobutyrate (Li-iPrIB) in toluene at −78 °C, affording highly isotactic polymers. Similarly, the polymerization of ethyl ester (2-MOM) gave an isotactic polymer, while those of t-butyl (3-MOM) and isobutyl (4-MOM) ester did not form any polymeric products. The hydrolysis of poly(2-MOM) in acidic conditions resulted in the deprotection of MOM group, although the acid also catalyzed the ester exchange between the neighboring units to form lactone units, as observed by 1H NMR analysis, IR spectroscopy and thermogravimetric analysis. A film of poly(2-MOM) exposed to HCl vapor for 2 h became insoluble in any organic solvents due to the lactonization in solid state.ArticleMacromolecular Symposia.350(1):86-98(2015)journal articl