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Scots pine (Pinus sylvestris L.) sapwood modification by vinyl acetate-epoxidized plant oil copolymer

precursor syntheses, characterization, modified wood properties and durability

Cai, Shengzhen (2016). Scots pine (Pinus sylvestris L.) sapwood modification by vinyl acetate-epoxidized plant oil copolymer. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae, 1652-6880 ; 2016:126
ISBN 978-91-576-8755-5
eISBN 978-91-576-8756-2
[Doctoral thesis]

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Abstract

A new bio-based formulation consisting of plant oil and vinyl acetate was developed for wood modification aiming at improving some of the material’s properties. In–situ epoxidation of linseed oil (LO) and soybean oil (SO) was carried out at different times with purpose of preparing epoxidized oils with various epoxy content. For comparison, commercially available epoxidized linseed oil (ELO®) and epoxidized soybean oil (ESO®) were also included in the study. The epoxidized oils were subsequently reacted with vinyl acetate (VAc) to investigate the effect of epoxidation degree on the copolymerization reaction between epoxidized oils and VAc. Results showed that a copolymer can be formed between VAc and epoxidized LO with high epoxy content, while no reaction occurred between VAc and SO or its epoxidized derivatives. As the most reactive monomer among studied oils, the epoxidized LO with highest epoxy content (i.e. ELO®) was selected for further investigation to determine the optimal conditions for its copolymerization reaction with VAc. The effect of feed ratio, reaction temperature, reaction time and catalyst amount on the efficiency of the copolymerization reaction was evaluated by measuring the yields of formed copolymer under different conditions. DSC and NMR were used to confirm the formation of copolymer and reveal the chemical structure of the obtained copolymer.

The optimized formulation was further impregnated into wood and subsequently cured, and the progress of curing process monitored using ATR–FTIR spectroscopy. It was found that an increase of curing temperature or duration resulted in improved wood dimensional stability, while weight percentage gain (WPG) was not significantly affected. In addition, insignificant correlation between WPG and anti–swelling efficiency (ASE) was found for the VAc–ELO® treated wood. From energy saving and economical point of view, 168 h of curing duration at 90°C is sufficient to achieve a satisfying dimensional stability. Moreover, the VAc–ELO® treated wood showed great leaching resistance to water. By using light– and scanning electron microscopy, it was found that the copolymer formed inside wood was mainly located in rays, resin canals and occasionally in the cell lumina. Like most wood treatments, the mechanical properties of VAc–ELO® treated wood samples were slightly decreased compared to untreated wood, especially MOR, compression parallel to the grain (∥) and hardness perpendicular to the grain (⊥). The difference between control and treated samples gradually increase as a result of increasing WPG. Durability tests showed that 8% WPG was enough to ensure decay resistance against the tested fungi (improved up to durability class 2), and thus can be used to protect wood used in above ground applications.

Authors/Creators:Cai, Shengzhen
Title:Scots pine (Pinus sylvestris L.) sapwood modification by vinyl acetate-epoxidized plant oil copolymer
Subtitle:precursor syntheses, characterization, modified wood properties and durability
Series/Journal:Acta Universitatis agriculturae Sueciae (1652-6880)
Year of publishing :2016
Depositing date:25 November 2016
Volume:2016:126
Number of Pages:71
Papers/manuscripts:
NumberReferences
IJebrane, M., Cai, S., Panov, D., Yang, X. & Terziev, N. (2015). Synthesis and characterization of new vinyl acetate grafting onto epoxidized linseed oil in aqueous media. Journal of applied polymer science, 132(24), pp. 42089.
IICai, S., Jebrane, M. & Terziev, N. (2016). Curing of wood treated with vinyl acetate–epoxidized linseed oil copolymer (VAc–ELO). Holzforschung, 70(4), pp. 305–312.
IIICai, S., Jebrane, M., Terziev, N. & Daniel, G. (2016). Mechanical properties and decay resistance of Scots pine (Pinus sylvestris L.) sapwood modified by vinyl acetate–epoxidized linseed oil copolymer. Holzforschung, 70(9), pp. 885–894.
IVCai, S., Jebrane, M., & Terziev, N. (2014). Properties of epoxidized linseed oil–furfuryl alcohol & vinyl acetate–furfuryl alcohol treated wood. Proceedings of the 10th meeting of the northern European network for wood science and engineering, Edinburgh, Scotland, 13–14 October 2014.
VJebrane, M., Cai, S., Sandström, C., & Terziev, N. (2016). The reactivity of linseed and soybean oil with various epoxidation degree towards vinyl acetate and impact of the resulting copolymer on the wood durability (submitted to Express Polymer Letters).
Place of Publication:Uppsala
Publisher:Department of Forest Products, Swedish University of Agricultural Sciences
ISBN for printed version:978-91-576-8755-5
ISBN for electronic version:978-91-576-8756-2
ISSN:1652-6880
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:K Forestry > K01 Forestry - General aspects
X Agricola extesions > X50 Chemistry
X Agricola extesions > X60 Technology
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 104 Chemical Sciences > Polymer Chemistry
(A) Swedish standard research categories 2011 > 2 Engineering and Technology > 204 Chemical Engineering > Polymer Technologies
(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Forest Science
Agrovoc terms:pinus sylvestris, sapwood, plant oils, polymers, acetates, epoxy compounds, wood preservation, wood properties, mechanical properties, wood decay, spectroscopy
Keywords:copolymer, curing, dimensional stability, durability, epoxidation, epoxidized linseed oil, leachability, mechanical properties, vinyl acetate, wood
URN:NBN:urn:nbn:se:slu:epsilon-e-3809
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-3809
ID Code:13866
Faculty:S - Faculty of Forest Sciences
Department:(S) > Dept. of Forest Products
Deposited By: Shengzhen Cai
Deposited On:28 Nov 2016 10:26
Metadata Last Modified:28 Nov 2016 10:26

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