Polyurethanes (PUs), in the form of coatings, adhesives, sealants, elastomers, and foams, play a vital role in the consumer goods, automotive, and construction industries. However, the inevitable disposal of nondegradable postconsumer polyurethane products constitutes a massive waste management problem that has yet to be solved. We address this challenge through the synthesis of biobased and chemically recyclable polyurethanes. Our approach employs renewable and degradable hydroxy telechelic poly(β-methyl-δvalerolactone) as a replacement for petroleum-derived polyols in the synthesis of both thermoplastic polyurethanes and flexible foams. These materials rival petroleum-derived PUs in performance and can also be easily recycled to recover βmethyl-δ-valerolactone monomer in high purity and high yield. This recycling strategy bypasses many of the technical challenges that currently preclude the practical chemical recycling of PUs.

We report the facile synthesis of well-defined ABA poly­(lactide)-block-poly­(styrene)-block-poly­(lactide) (LSL) triblock copolymers having a disperse poly­(styrene) midblock (Đ = 1.27–2.24). The direct synthesis of telechelic α,ω-hydroxy­poly­(styrene) (HO-PS-OH) midblocks was achieved using a commercially available difunctional free radical diazo initiator 2,2′-azobis­[2-methyl-N-(2-hydroxy­ethyl)­propionamide]. Poly­(lactide) (PLA) end blocks were subsequently grown from HO-PS-OH macroinitiators via ring-opening transesterification polymerization of (±)-lactide using the most common and prevalent catalyst system available, tin­(II) 2-ethylhexanoate. Fourteen LSL triblock copolymers with total molar masses M n,total = 24–181 kg/mol and PLA volume fractions f PLA = 0.15–0.68 were synthesized and thoroughly characterized. The self-assembly of symmetric triblocks was analyzed in the bulk using small-angle X-ray scattering and in thin films using grazing incidence small-angle X-ray scattering and atomic force microscopy. We demonstrate both the bulk and thin film self-assembly of LSL disperse triblocks gave well-organized nanostructures with uniform domain sizes suitable for nanopatterning applications.