PHBV-graft-GMA via reactive extrusion and its use in PHBV/nanocellulose crystal composites

Ting Zheng; Zhan Zhang; Srishti Shukla; Shubh Agnihotri; Craig M. Clemons; Srikanth Pilla

doi:10.1016/j.carbpol.2018.10.014

Treesearch

PHBV-graft-GMA via reactive extrusion and its use in PHBV/nanocellulose crystal composites

Formally Refereed

Authors:

Ting Zheng, Zhan Zhang, Srishti Shukla, Shubh Agnihotri, Craig M. Clemons, Srikanth Pilla

Year:

2019

Type:

Scientific Journal

Station:

Forest Products Laboratory

DOI:

https://doi.org/10.1016/j.carbpol.2018.10.014

Source:

Carbohydrate Polymers. 205: 27-34.

Download (PDF 2.31 MB)

Download (PDF 2.31 MB): https://research.fs.usda.gov/download/treesearch/58841.pdf

Abstract

Reactive extrusion was used for dicumyl peroxide (DCP)-initiated grafting of glycidyl methacrylate (GMA) to poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). The effects of GMA and DCP content and their weight ratio on the GMA grafting percentage (GP%), the polymer melt viscosity, and the PHBV molecular weight were investigated. FTIR spectroscopy determined that the DCP did indeed initiate GMA grafting. However, the changes in both the zero-shear viscosity (η₀) and the molecular weight suggested the existence of crosslinking products in the extruded polymers. A negative correlation between the degree of crystallinity (χ_c) of the PHBV-g-GMA and the GP% suggested the influence of chain branching on crystallinity. In addition, the GMA content was found as a key factor determining the GP%. The PHBV-g-GMA was used as a matrix polymer in cellulose nanocomposites to evaluate its effects on CNC dispersion and CNC-matrix adhesion relative to the unmodified PHBV matrix. The SEM images and the change in crystallization temperature suggested enhanced dispersion of CNC in a PHBV-g-GMA matrix. However, little increase in strength properties were found with CNC addition suggesting inadequate stress transfer between the matrix and CNCs.

Keywords

PHBV, cellulose nanocrystal, extrusion, injection molding, nanocomposite

Citation

Zheng, Ting; Zhang, Zhan; Shukla, Srishti; Agnihotri, Shubh; Clemons, Craig M.; Pilla, Srikanth. 2019. PHBV-graft-GMA via reactive extrusion and its use in PHBV/nanocellulose crystal composites. Carbohydrate Polymers. 205: 27-34.