Toughening polylactide with a catalyzed epoxy‐acid interfacial reaction

Abstract

Polylactide (PLA) is a promising material, with favorable modulus, renewable sources, and biodegradability. However, its low extension at break (4–7%) and toughness (notched Izod, 26 J/m) limit its applications (Anderson et al., Polym. Rev., 48, 85 (2008)). PLA toughening has been the subject of recent reviews, and is the basis for several commercial products. This work aims to increase PLA toughness using rubbery, linear low‐density polyethylene (LLDPE), glycidyl methacrylate functional PE compatibilizer (EGMA), and novel catalysts that promote copolymer formation at the interface of immiscible blends of PLA and EGMA/LLDPE. Droplet size was reduced from 2.7 µm to 1.7 µm with addition of 5 wt% EGMA, and further to 1.0 µm with the addition of cobalt octoate catalyst. Extension at break of 200% is achieved with only 5 wt% EGMA, 15 wt% LLDPE, and 0.01 M cobalt octoate, leading to an increase in tensile toughness of over an order of magnitude (compared to neat PLA). This work demonstrates that catalysts can reduce the amount of reactive compatibilizer necessary to achieve a given PLA toughness. POLYM. ENG. SCI., 58:28–36, 2018. © 2017 Society of Plastics Engineers

Epoxidized Block and Statistical Copolymers Reinforced by Organophosphorus–Titanium–Silicon Hybrid Nanoparticles: Morphology and Thermal and Mechanical Properties

“…On the basis of previous studies demonstrating that polymers with higher density have dark contrast by HAADF, , we propose that the darker regions correspond to the cross-linked GMA segments. The observation of phase-separation based on different mass densities has been previously reported in nonreactive block copolymers , and cross-linked block copolymers. − …”

“…The observation of phase-separation based on different mass densities has been previously reported in nonreactive block copolymers 73 , 74 and cross-linked block copolymers. 75 − 77 …”

Accelerating the Coupling of Maleated Polyolefins with Polyesters via Tin Compounds

“…To investigate the effect of moisture or nitrogen gas (discussed in the Supporting Information), the same procedure was performed using a smaller microcompounder (MC5, Xplore Instruments) or a Thermo-Haake internal batch mixer (maximum capacity: 50 mL; roller blades) to record the force (or torque with batch mixer) as a function of processing time. The recorded force was used as an analogue for changes in viscosity. , …”

“…The recorded force was used as an analogue for changes in viscosity. 13,14 For screening purposes, various catalysts (1.5 wt %) known to promote esterification were mixed with HDPE-MAH and PET (70/ 30 w/w) in the MC5 at 270 °C. The polymers were dried in a vacuum oven at 60 °C overnight.…”

Modification of reactive PB‐g‐SAG core–shell particles to achieve higher toughening ability for brittle polylactide

“…Therefore, how to improve the toughness of brittle PLA has become a research focus to promote its massive substitution of traditional petroleumbased polymers and widespread utilization. [7][8][9][10] Toughening strategies such as copolymerization, [11,12] plasticization, [13][14][15] and elastomer modification [16][17][18][19] have already been successfully employed to improve the toughness of PLA. In recent years, biodegradable tougheners also were prepared and applied to toughen PLA in order to achieve fully biodegradable properties.…”