scholarly journals Fully Biobased Shape Memory Thermoplastic Vulcanizates from Poly(Lactic Acid) and Modified Natural Eucommia Ulmoides Gum with Co-Continuous Structure and Super Toughness

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2040 ◽  
Author(s):  
Yan Wang ◽  
Jinhui Liu ◽  
Lin Xia ◽  
Mei Shen ◽  
Liping Wei ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Shape Memory ◽  
Poly Lactic Acid ◽  
Eucommia Ulmoides ◽  
Dynamic Vulcanization ◽  
Continuous Structure ◽  
Continuous State ◽  
Thermoplastic Vulcanizates ◽  
Potential Applications ◽  
Eucommia Ulmoides Gum

Novel, fully biobased shape memory thermoplastic vulcanizates (TPVs) were prepared using two sustainable biopolymers, poly(lactic acid) (PLA), and modified natural Eucommia ulmoides gum (EUG-g-GMA), via a dynamic vulcanization technique. Simultaneously, in situ compatibilization was achieved in the TPVs to improve interfacial adhesion and the crosslinked modified Eucommia ulmoides gum (EUG) was in “netlike” continuous state in the PLA matrix to form “sea-sea” phase structure. The promoted interface and co-continuous structure played critical roles in enhancing shape memory capacity and toughness of the TPVs. The TPV with 40 wt % modified EUG displayed the highest toughness with an impact strength of 54.8 kJ/m2 and the most excellent shape memory performances with a shape fixity ratio (Rf) of 99.83% and a shape recovery ratio (Rr) of 93.74%. The prepared shape memory TPVs would open up great potential applications in biobased shape memory materials for smart medical devices.

scholarly journals Bonding Wood Veneer with Biobased Poly(Lactic Acid) Thermoplastic Polyesters: Potential Applications for Consolidated Wood Veneer and Overlay Products

Fibers ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 50
Author(s):  
Warren J. Grigsby ◽  
Arpit Puri ◽  
Marc Gaugler ◽  
Jan Lüedtke ◽  
Andreas Krause
Keyword(s):  
Tensile Strength ◽  
Lactic Acid ◽  
Cold Water ◽  
Performance Criteria ◽  
Poly Lactic Acid ◽  
Wood Veneer ◽  
Pressing Temperature ◽  
Strength Performance ◽  
Potential Applications ◽  
Laminated Panels

This study reports on the use of poly(lactic acid) (PLA) as a renewable thermoplastic adhesive for laminated panels using birch, spruce, and pine veneers. Consolidated panels were prepared from veneer and PLA foils by hot-pressing from 140 to 180 °C to achieve minimum bondline temperatures. Evaluation of panel properties revealed that the PLA-bonded panels met minimum tensile strength and internal bond strength performance criteria. However, the adhesion interface which developed within individual bondlines varied with distinctions between hardwood and softwood species and PLA grades. Birch samples developed greater bondline strength with a higher pressing temperature using semi-crystalline PLA, whereas higher temperatures produced a poorer performance with the use of amorphous PLA. Panels formed with spruce or pine veneers had lower bondline performance and were also similarly distinguished by their pressing temperature and PLA grade. Furthermore, the potential for PLA-bonded laminated panels was demonstrated by cold water soak testing. Samples exhibiting relatively greater bondline adhesion had wet tensile strength values comparable to those tested in dry state. Our study outcomes suggest the potential for PLA bonding of veneers and panel overlays with the added benefits of being renewable and a no added formaldehyde system.

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