Poly(alkanoyl isosorbide methacrylate)s: From Amorphous to Semicrystalline and Liquid Crystalline Biobased Materials.

Siim Laanesoo,Patric Jannasch,Livia Matt,Jaan Parve,Olivier Bonjour,Lauri Vares,Omar Parve

doi:10.1021/acs.biomac.0c01474

Siim Laanesoo, Patric Jannasch + Show 5 more

Open Access

https://doi.org/10.1021/acs.biomac.0c01474

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Abstract

We have prepared a series of 12 d-isosorbide-2-alkanoate-5-methacrylate monomers as single regioisomers with different pendant linear C2–C20 alkanoyl chains using biocatalytic and chemical acylations. By conventional radical polymerization, these monomers provided high-molecular-weight biobased poly(alkanoyl isosorbide methacrylate)s (PAIMAs). Samples with C2–C12 alkanoyl chains were amorphous with glass transition temperatures from 107 to 54 °C, while C14–C20 chains provided semicrystalline materials with melting points up to 59 °C. Moreover, PAIMAs with C13–C20 chains formed liquid crystalline mesophases with transition temperatures up to 93 °C. The mesophases were studied using polarized optical microscopy, and rheology showed stepwise changes of the viscosity at the transition temperature. Unexpectedly, a PAIMA prepared from a regioisomeric monomer (C18) showed semicrystallinity but not liquid crystallinity. Consequently, the properties of the PAIMAs were readily tunable by controlling the phase structure and transitions through the alkanoyl chain length and the regiochemistry to form fully amorphous, semicrystalline, or semi/liquid crystalline materials.

Highlights

Consumption of finite fossil resources combined with growing environmental concerns is a strong driving force to phase out oil-based chemical processes and utilize renewable biomass as a source for chemicals and plastics.[1]
A two-step lipase-catalyzed process was used for the regioselective synthesis of several diester monomers
We have successfully prepared and systematically explored a series of 12 isosorbide-based AIMA monomers with different pendant linear alkanoyl chains having lengths spanning from C2 to C20

Summary

■ INTRODUCTION

Consumption of finite fossil resources combined with growing environmental concerns is a strong driving force to phase out oil-based chemical processes and utilize renewable biomass as a source for chemicals and plastics.[1]. The monomers were employed in conventional free-radical polymerizations, and the resulting poly(alkanoyl isosorbide methacrylate)s (PAIMAs) were characterized by thermogravimetry, calorimetry, rheology, dynamic mechanical starting temperature at the same heating rate. As reported by Matt et al, the first step most likely corresponds to the decomposition of the alkanoyl chains, and the second step to the degradation of the isosorbide units, followed by a gradual decomposition of the polymer backbone.[24] The plot of Td,[95] versus the number of carbon atoms in the pendant alkanoyl chain shows an initial decrease from 238 °C for the non-alkanoylated PAIMA024 to 190 and 188 °C for PAIMA4 and PAIMA6, respectively. Đc (T°Cd,9)5d (°TCg)e (°TCm)e (°TCc)e (JΔgH−1m)e (°CT)i e,f (°CT)ae,g (JΔgH−1i)e

15 PAIMA20

■ CONCLUSIONS

■ ACKNOWLEDGMENTS

■ REFERENCES