Synthesis, Structures And Properties Of Organosilicon Supramolecular Polymers Constructed By Hydrogen Bonds

Supramolecular polymers, as a potential and interesting class of stimuli- or environmentally responsive "intelligent" materials, have attracted great research interest in polymer science. They are arrays of low or high molar mass molecules or conventional polymers reversibly self-assembled through noncovalent interactions. Various types of noncovalent interactions can be used in the preparation of supramolecular polymers:hydrogen bonding, electrostatic forces, vander Waals interactions, metal-ligand coordination, etc. Among these interactions, the combination of hydrogen bonding with other weak reversible interactions such asπ-πstacking can make a principal contribution in the design of novel polymer architectures and control and improvement of polymer properties due to their directionality and versatility.Silicone polymer is the first element polymers which are applied in industry and also are the fastest branches in development of element organ polymer field. It presents a lot of unique and excellent properties. Organosilicon supramolecular polymer through hydrogen bonding association is a novel field in organosilicon chemistry and has extensive using value. In this paper, the study was mainly on the synthesis, structures and properties of organosilicon supramolecular polymer via intermolecular hydrogen bonds. It was divided into two parts:The first part was the synthesis of a new thermosensitive material from linear polydimethylsiloxane via weak hydrogen bond supramolecular self-assembly. It was prepared by coupling the N-pyridin-2-yl-succinamic acid with aminopropyl-terminated polydimethylsiloxane via amidated reaction. We have demonstrated the existence of intermolecular hydrogen bonding,π-πstacking, phase segregation in supramolecular aggregation and obtained the possible self-assembly structure. The self-assembly structure was crucial to the preparation of thermosensitive material. In addition, their rheological behaviors were strongly different due to the self-assembly units at different temperature. And the molecular weight had not a great influence on thermal sensitivity but had a strong influence on morphology of supramolecular aggregation at room temperature. It should be an important design parameter for the development of new highly thermally responsive and intelligent materials. Because the rate of decomplexation of the end units, the compatibility of the hard and soft blocks can both be adjusted to alter the equilibrium or binding constant.The second part was the synthesis of a new organosilicon plastic elastomer based on strong hydrogen-bonding interactions. We have applied strongly dimerizing ureidopyrimidinone (UPy) quadruple hydrogen-bonding units as physical cross-linker, which was one of the most elegant and successfully employed motifs for supramolecular polymerizations. The differential scanning calorimetry (DSC) measurements and tensile testing were carried out to investigate the nature of elastomers. The results indicated that the average molecular weight of aminopropyl-terminated polydimethylsiloxane has a great impact on the mechanical property of elastomer. An appropriate molecular weight of it was obtained for the preparation of elastomer with good mechanical properties. That is, the variation in the number of UPy units in the polymeric backbone can be used to tailor the properties of these kinds of materials. In addition, materials properties can be also tuned by changing the spacer that contains the hydrogen-bonded units.The study which was on the synthesis, structure and properties of organosilicon supramolecular polymer provided the experimental and theoretical foundation for the preparation of advanced materials possessing good properties.