Cyclic-acyclic monomers metathesis polymerization to access photodegradable polydicyclopentadiene and polyethylene-like materials

The development of degradable and recyclable polymers is an attractive strategy to tackle the post-consumption pollution issue of commercial plastics.Cyclic-acyclic monomers metathesis polymerization(CAMMP)has been recently reported to produce degradable thermoset,thermoplastic and elastomeric polymers,and their degradability is enabled with addition of various chemicals.In this contribution,we demonstrate that the utilization of diene comonomers containing photodegradable moiety can give access to thermoset and thermoplastic materials bearing photo-degradation capabilities.The copolymerization of a series easily accessible diene comonomers bearing photodegradable ortho-nitrobenzyl moieties with dicyclopentadiene(DCPD)or cyclooctene(COE)leads to the formation of photodegradable p DCPD thermosets and p COE thermoplastic polymers with mechanical properties comparable to their non-degradable counterparts.Most importantly,their photo-degradation properties can be efficiently tuned with the addition of ultraviolet absorber during in-situ polymerization.

Controlled Ring-opening(Co)Polymerization of Renewable Macrolactones by Al-based Catalysts with Different Sidearms

It remains a challenging task to achieve ring-opening(co)polymerization(ROP)of macrolactones.Hence,we synthesized a series of Al-based catalysts and systemically investigated the effect of N-containing substituent on the sidearms on ROP of macrolactones.Al3 possessing Nmethyl group could effectively achieve controlled ROP of pentadecalactone(PDL)and macro(di)lactone ethylene brassylate(EB)in combination with BnOH,furnishing polyethylene-like PPDL and PEB with M_(W)up to 90.3 and 321 kg/mol,respectively.Random copolymerization of PDL and small-ring lactonesε-caprolactone(e-CL)andδ-valerolactone(δ-VL)could prepare random copolyesters with tailored T_(m)in the range of 57-94℃by controlling the ratios of PDL and e-CL,6-VL.More importantly,well-defined block copolyesters could be obtained by sequential adding PDL andε-CL,δ-VL,which have been proved by GPC-MALLS,DSC and^(13)C-NMR.