Currently, most commodity chemicals and polymers are manufactured from nonrenewable petroleum-based resources. However, due to its finite nature and social claims about environment preservation, alternative sources of value-added and building block chemicals are being intensively studied. Renewable lignocellulosic biomass has offered an attractive replacement for fossil-based chemicals. Lignin and C5/C6 sugars obtained from lignocellulosic biomass through chemical and enzymatic methods can be further transformed to targeted chemical platforms. In the present review, synthetic pathways for well-defined poly(meth)acrylates obtained from C5/C6 sugar-derived platforms in which the sugar structure is not retained are discussed. While bio-based polymers from these monomers are investigated using a wide range of polymerization techniques, this study focuses on precise synthesis of macromolecular structures taking advantage of reversible-deactivation radical polymerization methods and their applications.

We report the synthesis and solution properties of novel biobased thermoresponsive amphiphilic copolymers prepared using N,N-dimethyl lactamide acrylate (DMLA) and ethyl lactate acrylate (ELA) as hydrophilic and hydrophobic monomers, respectively. Copolymers with similar overall molecular weight but different monomer distribution profiles, such as random, diblock, triblock, and random−blocks, were prepared using photoinduced electron/energy transfer-reversible addition−fragmentation chain transfer (PET-RAFT) polymerization activated by a Zn-based photoredox catalyst. The synthesized polymers show interesting self-assembly and thermoresponsive behavior in water, depending on the monomers distribution along the chain. Different critical solution temperatures, in the range of 13−70 °C, were observed by tuning the monomers molar ratio and distribution. The formation of aggregates of various types was proven by transmission electron microscopy (TEM). The prepared polymers also display different surface activity with the fully random copolymer being significantly more surface active than block systems. A study of emulsion stabilization was performed with oils of various polarity, showing promising results for applications of these novel polymers as biobased surfactants and water/oil (w/o) emulsion stabilizers.

A solvent-to-polymer upgrading strategy was developed to convert green solvents of the lactic acid portfolio into LCST-type acrylic polymers and hydrogels.

This work demonstrates for the first-time biobased, temperature-responsive diblock copolymer nanoparticles synthesized by reversible addition−fragmentation chain-transfer (RAFT) aqueous emulsion polymerization-induced self-assembly (PISA). Here, monomers derived from green solvents of the lactic acid portfolio, N,N-dimethyl lactamide acrylate (DMLA) and ethyl lactate acrylate (ELA), were used. First, DMLA was polymerized by RAFT aqueous solution polymerization to produce a hydrophilic PDMLA macromolecular chain transfer agent (macro-CTA), which was chain extended with ELA in water to form amphiphilic PDMLA-b-PELA diblock copolymer nanoparticles by RAFT aqueous emulsion polymerization. PDMLA x homopolymers were synthesized targeting degrees of polymerization, DP x from 25 to 400, with relatively narrow molecular weight dispersities (Đ < 1.30). The PDMLA 64 -b-PELA y diblock copolymers (DP y = 10−400) achieved dispersities, Đ, between 1.18 and 1.54 with two distinct glass transition temperatures (T g ) identified by differential scanning calorimetry (DSC). T g(1) (7.4 to 15.7 °C) representative of PELA and T g(2) (69.1 to 79.7 °C) of PDMLA. Dynamic light scattering (DLS) studies gave particle z-average diameters between 11 and 74 nm (PDI = 0.04 to 0.20). Atomic force microscopy (AFM) showed evidence of spherical particles when dispersions were dried at ∼5 °C and film formation when dried at room temperature. Many of these polymers exhibited a reversible lower critical solution temperature (LCST) in water with a concomitant increase in zaverage diameter for the PDMLA-b-PELA diblock copolymer nanoparticles.

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