Synthesis Of Cross-linked Degradable Polymer Material Based On Thioketal Cleavable Monomer

Thermosets are rigid,infusible,and unmolded materials containing 3D cross-linked structures.Thermosets are considered a fundamental pillar in the international economy,which are produced by 65 million tons annually.The responsive cross-linking moieties provide the thermosets with outstanding physicochemical properties such as stiffness,degradability,chemical,and thermal resistance.We prepared three crosslinkers for degradable thermosets using diacrylamide crosslinker(Tk-1),diamine crosslinker(Tk-2),and diol crosslinker(Tk-3),which underwent degradation in the presence of hydrogen peroxide in water.Diacrylamide crosslinker(Tk-1)at different concentrations(5%,10%,and 20%,w%)was polymerized with 2-hydroxyethyl acrylate(HEA)to produce cross-linked Tk-poly(HEA)in bulk polymerization.The cross-linked Tk-poly(HEA)showed fast and complete degradation within 60 h at 37oC in H₂O₂/water solution(30%,v/v).We observed that the higher the concentration of H₂O₂ resulted in a faster degradation rate.The crosslinker(Tk-1)copolymerized with 2-hydroxyethyl methacrylate and 1-vinyl-2-pyrrolidone(poly(HEMA-PD))to produce a degradable material that could be used for contact eye lens.The cross-linked poly(HEMA-PD)degraded entirely within 10 days at room temperature(RT)in H₂O₂/water solution(30%,v/v).The crosslinker(Tk-3)polymerized with isophorone diisocyanate(IPDI)to produce degradable polyurethane,used to make gloves and catheters as samples.The gloves degraded within 5 days at RT in H₂O₂(30%).Due to the supreme importance of 3D printing in material construction,we also employed the Direct-Ink-Writing(DIW)machine which was charged by diacrylamide cross linker(15%Tk-1,w%)and a prepolymer(isophorone diisocyanate-terminated by acrylate moieties)to prepare a 3D degradable thermoset under UV-photocuring.The 3D thermoset degraded completely within 24h at RT in H₂O₂(30%).