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Grafting of polycaprolactone from microfibrillated cellulose and the investigation of graft lengths impact on the mechanical properties innano-biocomposites
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.ORCID iD: 0000-0002-9372-0829
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.ORCID iD: 0000-0002-8348-2273
(English)Manuscript (Other academic)
Keyword [en]
biocomposites, microfibrillated cellulose, polycaprolactone, grafting from, graft length
National Category
Chemical Sciences
URN: urn:nbn:se:kth:diva-10481OAI: diva2:217950
QC 20100729Available from: 2009-05-18 Created: 2009-05-18 Last updated: 2010-07-30Bibliographically approved
In thesis
1. Ring-opening polymerization from cellulose for biocomposite applications
Open this publication in new window or tab >>Ring-opening polymerization from cellulose for biocomposite applications
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

There is an emerging interest in the development of sustainable materials with high performance. Cellulose is promising in this regard as it is a renewablere source with high specific properties, which can be utilized as strong reinforcements in novel biocomposites. However, to fully exploit the potential ofcellulose, its inherent hydrophilic character has to be modified in order toimprove the compatibility and interfacial adhesion with the more hydrophobicpolymer matrices commonly used in composites.In this study, the grafting of poly(ε-caprolactone) (PCL) and poly(L-lactide)(PLLA) from cellulose surfaces, via ring-opening polymerization (ROP) of ε-caprolactone and L-lactide, was investigated. Both macroscopic and nano-sizedcellulose were explored, such as filter paper, microfibrillated cellulose (MFC),MFC-films, and regenerated cellulose spheres. It was found that thehydrophobicity of the cellulose surfaces increased with longer graft lengths, andthat polymer grafting rendered a smoother surface morphology.To improve the grafting efficiency in the ROP from filter paper, both covalent(bis(methylol)propionic acid, bis-MPA) and physical pretreatment (xyloglucanbisMPA)were explored. The highest grafting efficiency was obtained with ROPfrom the bis-MPA modified filter papers, which significantly increased amountof polymer on the surface, i.e. the thickness of the grafted polymer layer.MFC was grafted with PCL to different molecular weights. The dispersability innon-polar solvent was obviously improved for the PCL grafted MFC, incomparison to neat MFC, and the stability of the MFC suspensions was better maintained with longer grafts. PCL based biocomposites were prepared from neat MFC and PCL grafted MFCwith different graft lengths. The polymer grafting improved the mechanical properties of the composites, and the best reinforcing effect was obtained when PCL grafted MFC with the longest grafts were used as reinforcement.A bilayer laminate consisting of PCL and MFC-films grafted with different PCL graft lengths displayed a gradual increase in the interfacial adhesion with increasing graft length.The effect of grafting on the adhesion was also investigated via colloidal probeatomic force microscopy at different temperatures and time in contact. A significant improvement in the adhesion was observed after polymer grafting.

Place, publisher, year, edition, pages
Stockholm: KTH, 2009. 68 p.
Trita-CHE-Report, ISSN 1654-1081 ; 2009:24
cellulose, ring-opening polymerization, polycaprolactone, grafting from
National Category
Other Basic Medicine
urn:nbn:se:kth:diva-10455 (URN)978-91-7415-338-5 (ISBN)
Public defence
2009-06-05, F3, KTH, Lindstedsvägen 26, Stockholm, 10:00 (English)
QC 20100730Available from: 2009-05-18 Created: 2009-05-15 Last updated: 2010-07-30Bibliographically approved

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