Tailor-Made Fibrous Hydroxyapatite/Polydimethylsiloxane Composites: Insight into the Kinetics of Polymerization in the Presence of Filler and Structure-Property Relationship

摘要

A scrupulously manipulated rate acceleration of anionic ring-opening polymerization of octamethylcyclotetra-siloxane (D4), a precursor for polydimethylsiloxane (PDMS) was designed and executed using hydroxyapatite (HA) fiber surface coated with polyethyleneglycol (PEG) as the rate accelerator. Kinetics of polymerization was investigated through programmed FTIR analysis. In this paper, the beneficial role of HA as a polymerization rate promoter was investigated and hence established. In addition, PEG molecules on the filler surface acted as the activator in the polymerization reaction. Hence, a synergism of these two independent effects resulted in a momentous increase in the rate of polymerization. The rate of reaction was found to increase from 6.35 X 10~(-2) to 10.32 X 10~(-2) s~(-1) in the presence of 4 wt % of HA filler. A morphology—property relationship was established for these tailor-made composites to explore the diverse fields of application of these advanced materials. Although the in situ prepared sample showed a 260% increase in tensile modulus, an increase of 210% was observed for the ex situ prepared composite at 2 wt % filler loading. Dispersion of HA filler in the polymer matrix is the crucial parameter in improving the physicomechanical properties of the composites.