Qiujin Li

Rheological Properties and Microstructures of Hydroxyethyl Cellulose/Poly(Acrylic Acid) Blend Hydrogels

A simple in-situ method was introduced to prepare hydroxyethyl cellulose/poly(acrylic acid) (HEC/PAA) blend hydrogels by forming an interpenetrating network (IPN). Storage modulus (G′) and loss modulus (G″) were improved dramatically compared to HEC. To prove that hydrogen bonds and chemical crosslinking played major roles in improving the hydrogel strength and toughening, and to optimize the components of HEC/PAA blend hydrogels, a series of blend hydrogels with different ratios of HEC to PAA were designed and the corresponding Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), rheological tests, and swelling properties were compared. Crosslinked HEC/PAA blend hydrogel (mol/mol = 1:1) showed the best properties appropriate for opening up biomedical applications of the hydrogel.

Investigation of the degradation of bio-recalcitrance in Apocynum venetum fiber biodegumming

ABSTRACT Traditional degumming of bast fibers results in problems such as environmental pollution and inferior fiber quality. For these reasons, biodegumming was considered as a potential process for bast fibers. In biodegumming process, decomposition of noncellulosic components was the pivotal problem. In this manuscript, the bast fiber of Apocynum venetum was processed with combinatorial processing, containing physical, chemical and microbial effect. The structural bio-recalcitrance was analyzed at molecular, supermolecular and morphological level in each stage. The results show that main substance in recalcitrance of Apocynum venetum bast is lignin and hemicellulose. And the protein and wax is also the constituent of bio-recalcitrance. The recalcitrance in the bast tissue can be divided into three layers. The spatial structure and the distribution of the noncellulosic substances also contribute to the recalcitrance. This paper provides directions for pretreatment design to render biomass more amenable to bioprocessing.