Synthesis, Characterization, and Polymerization Kinetics of Novel Ladder-Like Polysilsesquioxanes Containing Side-Chain Propyl Methacrylate Groups

• Published in: Macromolecular chemistry and physics Vol. 204; no. 3; pp. 531 - 539
• Main Authors: Gopala Krishnan, P. Santhana, He, Chaobin
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.03.2003; WILEY‐VCH Verlag; Wiley
• Subjects: Applied sciences; crystallization; Exact sciences and technology; Inorganic and organomineral polymers; kinetics (polym.); methacrylate; Physicochemistry of polymers; polysilsesquioxanes; Preparation; synthesis; Methacrylate polymer; Silsesquioxane polymer; Molecular structure; Condensation polymerization; Silsesquioxane copolymer; Experimental study; Ladder polymer; Thermal stability; Crosslinked copolymer; Free radical polymerization; Preparation; Crosslinked polymer; Copolycondensation; Prepolymer; Methacrylate copolymer; Chemical reactivity
• ISSN: 1022-1352; 1521-3935
• DOI: 10.1002/macp.200390018

Three ladder‐like polysilsesquioxanes containing side‐chain propyl methacrylate groups have been synthesized successfully by stepwise coupling polymerization. The prepared ladder‐like polymers are polysilsesquioxanes containing 100 mol‐% propyl methacrylate side groups and two copolymers containing 70 mol‐% methyl or phenyl groups and 30 mol‐% propyl methacrylate side groups. They were characterized by FT‐IR, 1H NMR, proton‐decoupled 13C NMR, and 29Si NMR spectroscopies, gel‐permeation chromatography (GPC), wide‐angle X‐ray diffraction (XRD), differential scanning calorimetry (DSC), and thermo‐gravimetric analysis (TGA). Characterization data indicate that these polymers have ordered ladder‐like structures with possible defects. At appropriate conditions, crystals of homopolymer were grown and are in the shape of a parallelogram. All three polymers were cured by 2,2′‐azoisobutyronitrile (1% w/w) and the kinetics for the bulk polymerization of these polysilsesquioxanes was followed by dynamic DSC method. Ozawa and Kissinger methods were used to calculate the activation energy for curing. Both the frequency factor and the activation energy of the homopolymer were found to be higher than the copolymers. Cured samples had a higher thermal stability than uncured samples. Chemical structure of LPS.