Star-shaped lactic acid based systems and their thermosetting resins; synthesis, characterization, potential opportunities and drawbacks

Abstract

Shortcomings of the conventional PLA synthesis methods have encouraged researchers to investigate on alternative methods for PLA synthesis. Utilization of chain extenders is an effective way to achieve high MW polymers. The concept of using star-shaped resins as the reinforced matrices for biocomposites or in biomedical applications is gaining more and more attention day by day. Star-shaped lactic acid based resins are a class of branched resins with a multifunctional core molecule and lactic acid branches. In order to increase the reactivity of branches, the star-shaped resin oligomers can get end-functionalized which yields in a crosslinkable product. Changing the architecture of a polymer from a linear to a multiarm or hyperbranched one, would change its chemical, diffusional and physical-mechanical properties. This review paper presents the current state and recent advances in the synthesis, characterization, properties and applications of the star-shaped resins made from lactic acid and multi-hydroxyl core molecules with a focus on the role of the morphology of the polymer on the 3 properties of resins. Rheological, physiochemical and thermomechanical properties of to date synthesized star-shaped resins are compared and discussed. Special emphasis would be made on potential opportunities, probable applications and also gaps and drawbacks concerning these systems. This review aims to provide useful information to help future development of efficient, highly engineered bioresins which can be especially designed for a certain application.

Synthesis and characterization of methacrylated star‐shaped poly(lactic acid) employing core molecules with different hydroxyl groups

“…Another route has been to synthesize branched PLA, mainly for the use as thermosets. Different techniques have been employed for inducing branching points in the structure of PLA, including free‐radical branching in the presence of peroxides . The crosslinkable branched‐structure lowers the melt viscosity of the un‐cured resin, which enhances processability of the un‐cured resin and in the same time increases MW of the cured resin which in turn improves the mechanical properties of the cured resin.…”

Stereocomplexation, Thermal and Mechanical Properties of Conetworks Composed of Star-Shaped l-Lactide, d-Lactide and ε-Caprolactone Oligomers Utilizing Sugar Alcohols as Core Molecules

“…Teng and Nie et al reported the controlled drug-release behavior of star-shaped PLLAs with a SB core [22]. Recently, network polymers derived from terminal functionalized star-shaped biodegradable polyesters have gathered considerable attention since the curing reaction of their at least three functional groups easily generates crosslinked structures and the crosslinking density can be controlled by changing the arm length [3,13,[29][30][31][32][33][34][35][36][37][38]. For example, Storey et al reported the networks prepared by the crosslinking reaction of hydroxy-terminated 3-armed random copolymers of D,L-LA and CL with L-lysine diisocyanate [30].…”

“…Compared with linear analogs of equal molecular weight, they have a higher concentration of functional end groups, and often exhibit lower viscosities, different thermal and mechanical properties and improved physical processability, as their properties are more influenced by arm length than the total molecular weight. Recently, a number of researchers have focused on star-shaped biodegradable/biocompatible polyesters for biomedical applications, including drug delivery, gene delivery, tissue engineering, diagnosis and medical devices [1][2][3]. Until now, a variety including drug delivery, gene delivery, tissue engineering, diagnosis and medical devices [1][2][3].…”

“…Jahandideh et al reported the thermomechanical properties of cured products of methacrylate-functionalized star-shaped lactide oligomers with a XL core and their biocomposites with jute fibers [36]. Also, we reported pentaerythritol-based polymer networks (PEPN-4scLAO/2CLOs) prepared by reactions of methylenediphenyl 4,4′-diisocyanate (MDI), hydroxy-terminated two enantiomeric 4-armed star-shaped lactide oligomers bearing a pentaerythritol core (PE4LLAO and PE4DLAO) and a diethylene glycol-based hydroxy-terminated 2-armed ε-caprolactone oligomer (H2CLO) [37], and glycerol (GC)-based polymer networks (GCPN-3scLAO/2CLOs) by reactions of hexamethylene diisocyanate (HDI), hydroxy-terminated Recently, network polymers derived from terminal functionalized star-shaped biodegradable polyesters have gathered considerable attention since the curing reaction of their at least three functional groups easily generates crosslinked structures and the crosslinking density can be controlled by changing the arm length [3,13,[29][30][31][32][33][34][35][36][37][38]. For example, Storey et al reported the networks prepared by the crosslinking reaction of hydroxy-terminated 3-armed random copolymers of D,L-LA and CL with L-lysine diisocyanate [30].…”

“…Recently, a number of researchers have focused on star-shaped biodegradable/biocompatible polyesters for biomedical applications, including drug delivery, gene delivery, tissue engineering, diagnosis and medical devices [1][2][3]. Until now, a variety including drug delivery, gene delivery, tissue engineering, diagnosis and medical devices [1][2][3]. Until now, a variety of star-shaped biodegradable polyesters have been synthesized by the ring-opening polymerization of cyclic esters such as lactide (LA) [4][5][6][7], ε-caprolactone (CL) [8][9][10][11][12][13], β-butyrolactone [14,15] and trimethylene carbonate [16,17].…”