Author:

Keywords:

Science & Technology, Physical Sciences, Chemistry, Multidisciplinary, Chemistry, multidimensional NMR, oligomers, polyoligosiloxysilicone, polymers, silicon, BUILDING-BLOCK APPROACH, HYDRATE-TYPE MATERIALS, CRYSTAL-STRUCTURE, HYBRID MATERIALS, STRUCTURAL LINKS, NMR-SPECTROSCOPY, SILOXANE CAGES, ZEOLITE-TYPE, SPHEROSILICATE, NANOCOMPOSITES, METH/14/04#53291607, 03 Chemical Sciences, General Chemistry, 34 Chemical sciences

Abstract:

A new copolymer consisting of double four ring (D4R) silicate units linked by dimethylsilicone monomer referred to as polyoligosiloxysilicone number one (PSS-1) was synthesized. The D4R building unit is provided by hexamethyleneimine cyclosilicate hydrate crystals, which are dehydrated and reacted with dichlorodimethylsilane. The local structure of D4R silicate units and dimethyl silicone monomers was revealed by multidimensional solid-state NMR, FTIR and modeling. On average, D4R silicate units have 6.8 silicone linkages. Evidence for preferential unidirectional growth and chain ordering within the PSS-1 copolymer was provided by STEM and TEM. The structure of PSS-1 copolymer consists of twisted columns of D4R silicate units with or without cross-linking. Both models are consistent with the spectroscopic, microscopic and physical properties. PSS-1 chains are predicted to be mechanically strong compared to silicones such as PDMS, yet more flexible than rigid silica materials such as zeolites.