Poly(lactic acid)/pulp fiber composites: The effect of fiber surface modification and hydrothermal aging on viscoelastic and strength properties
2020 (English)In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 137, no 42, article id 49617Article in journal (Refereed) Published
Abstract [en]
Poly(lactic acid) (PLA)/kraft pulp fiber (30 wt%) composites were prepared with and without a coupling agent (epoxidized linseed oil, ELO, 1.5 wt%) by injection molding. The non-annealed composite samples, along with lean PLA, were exposed to two hydro-thermal conditions: cyclic 50% RH/90% RH at 23 and 50°C, both up to 42 days. The aging effects were observed by size exclusion chromatography, differential scanning calorimetry, dynamic and tensile mechanical analysis, and fracture surface imaging. ELO temporarily accelerated the material's internal transition from viscous to an increasingly elastic response during the aging at 50°C. ELO also slowed down the tensile strength reduction of the composites at 50°C. These observations were explained with the hydrophobic ELO molecules' coupling and plasticizing effects at fiber/matrix interfaces. No effects were observed at 23°C.
Place, publisher, year, edition, pages
John Wiley and Sons Inc. , 2020. Vol. 137, no 42, article id 49617
Keywords [en]
aging, biopolymers and renewable polymers, cellulose and other wood products, composites, Coupling agents, Differential scanning calorimetry, Injection molding, Lactic acid, Size exclusion chromatography, Tensile strength, Epoxidized linseed oil, Fiber surface modifications, Fiber/matrix interface, Hydrothermal aging, Internal transitions, Plasticizing effects, Tensile mechanical analysis, Tensile strength reductions, Fibers
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:ri:diva-45388DOI: 10.1002/app.49617Scopus ID: 2-s2.0-85087216834OAI: oai:DiVA.org:ri-45388DiVA, id: diva2:1455064
Note
CODEN: JAPNA; Funding details: Teknologian Tutkimuskeskus VTT; Funding text 1: The authors would like to thank Mr. Upi Anttila (VTT) and Mr. Eino Sivonen (VTT) for the preparation of the composite samples, and a number people at RISE Bioeconomy; Dr. Kristoffer Segerholm, Dr. Prashanth Srinivasa, Mr. Henrik Pettersson, Mr. Jens Haraldsson, Ms. Anna Östberg, Ms. Erika Back, for their help executing the experimental work in Stockholm in the spring 2019. The authors gratefully acknowledge the funding from VTT and RISE.
2020-07-222020-07-222021-03-26