Long chain branching (LCB) structures are efficiently introduced into polylactide (PLA) by employing sustainable soybean oil (SO) under the initiation of trace amount of cyclic peroxide, which displays robust foamability and heat resistance. It is discovered that with the introduction of 0.6 wt% SO, the expansion ratio and Vicat softening temperature of LCB PLA are sharply raised to 75.2-fold and 155.8 °C, respectively, which is about 17.9 and 2.6 times those of linear PLA. This is because that the amounts of LCB structures are significantly increased in LCB PLA by the addition of SO with low reactivity of internal CC bonds, which can avoid the oligomerization reaction, resulting in more dramatically improved melting strength and crystallization performance of LCB PLA. Moreover, the hydrolytic degradation of LCB PLA is largely expedited as compared to linear PLA, owing to the more rapid water permeation caused by the loose packing of LCB structures. Finally, the PLA foam tray with light weight and good heat resistance is successfully developed by using LCB PLA with 0.6 wt% SO through extrusion foaming with supercritical carbon oxide and thermoforming techniques. Hence, this research offers a green route to produce eco-friendly light-weight and high-heat-resistance LCB-PLA foam with full biodegradability, which is an ideal alternative to the non-degradable oil-based plastics in the field of disposable packaging products.
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http://dx.doi.org/10.1016/j.ijbiomac.2021.04.146 | DOI Listing |
Int J Biol Macromol
December 2024
POLYMAT and Department of Advanced Polymers and Materials: Physics, Chemistry and Technology, Faculty of Chemistry, University of the Basque Country UPV/EHU, Paseo Manuel de Lardizabal 3, 20018 Donostia-San Sebastián, Spain; IKERBASQUE, Basque Foundation for Science, Plaza Euskadi 5, 48009 Bilbao, Spain. Electronic address:
The generation of long-chain branches (LCB) in biobased and biodegradable polylactide (PLA) by adding different amounts of a chain extender is studied. The rheological and calorimetric behavior have been used to determine the effect of LCB presence and their topology on PLA melt strength and crystallization behavior. Rheological modeling of linear and non-linear viscoelastic shear and extensional properties identified several possible branched structures.
View Article and Find Full Text PDFMacromol Rapid Commun
March 2023
Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, 214122, China.
Polymer melt strength (MS) is strongly correlated with its molecular structure, while their relationship is not very clear yet. In this work, designable long-chain branched polylactide (LCB-PLA) is prepared in situ by using a tailor-made (methyl methacrylate)-co-(glycidyl methacrylate) copolymer (MG) with accurate number of reactive sites. A new concept of branching density (φ) in the LCB-PLA system is defined to quantitively study their relationship.
View Article and Find Full Text PDFInt J Biol Macromol
July 2021
College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering of China, Sichuan University, Chengdu 610065, PR China.
Long chain branching (LCB) structures are efficiently introduced into polylactide (PLA) by employing sustainable soybean oil (SO) under the initiation of trace amount of cyclic peroxide, which displays robust foamability and heat resistance. It is discovered that with the introduction of 0.6 wt% SO, the expansion ratio and Vicat softening temperature of LCB PLA are sharply raised to 75.
View Article and Find Full Text PDFJ Biomed Mater Res A
November 2019
School of Material Science and Engineering, Xihua University, Chengdu, China.
Long-chain branched poly (lactic acid) (LCB-PLA) with antimicrobial functional group was fabricated through a two-step ring-opening reactive processing for improving antimicrobial properties and broadening the PLA processing window. A combination of linear viscoelasticity and the branch-on-branch (BOB) model predicted probable compositions and chain topologies of the products. It is also explored the antimicrobial properties of LCB-PLA to provide a theoretical basis for broadening the possible applications.
View Article and Find Full Text PDFJ Biomed Mater Res A
July 2019
School of Engineering, Design and Technology, University of Bradford, Bradford, United Kingdom.
Highly oriented long-chain-branched poly(lactic acid) (LCB-PLA) was fabricated through solid-phase die drawing technology, and the in vitro degradation behavior of the oriented samples in phosphate-buffered saline (PBS) was studied. During degradation, the weight retention and molecular weight for both PLA and LCB-PLA increased with the increase of draw ratio. Moreover, the degradation autocatalytic effect was delayed, and the deterioration of mechanical strength was reduced by orientation, which was beneficial for controlling the degradation degree and decay rate of strength for PLA as bone fixation materials.
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