Carboxylated bleached kraft pulp from maleic anhydride copolymers

Seven copolymers of maleic anhydride were hydrolyzed and impregnated into sheets of bleached softwood kraft pulps to enhance market pulp properties. Drying the impregnated pulps at 120 °C for 10 minutes, attached to the fiber surfaces up 0.16 meq of carboxyl groups per gram of dry pulp. Heating the impregnated pulps regenerates succinic anhydride moieties which can then form stable ester linkages with cellulosic hydroxyls. The pH of the impregnation solution is important. Impregnation with solutions at pH 8 gave polymer contents without repulping issues. By contrast, impregnation at pH 4 gave dried pulp sheets that were too strong to enable repulping in a paper mill. Although most of the seven copolymers were fixed to cellulose, poly(ethylene-alt-maleic anhydride) gave the highest density of carboxyl groups. The simplicity of waterborne polymers and mild drying temperatures suggests maleic anhydride copolymer treatment could be implemented in a conventional market pulp mill.

Tough Hydrogels Based on Maleic Anhydride, Bulk Properties Study and Microfiber Formation by Electrospinning

Hydrogels present a great number of advantages, such as their swelling capacity or their capability to mimic tissues, which make them very interesting biomaterials. However, one of their main disadvantages is their lack of good mechanical properties, which could limit some of their applications. Several strategies have been carried out to develop hydrogels with enhanced mechanical properties, but many of the suggested synthetic pathways to improve this property are expensive and time consuming. In this work, we studied an easy synthetic path to produce tough hydrogels based on different maleic anhydride copolymers crosslinked with polyethylenglycol. The effect of the comonomers in the mechanical properties has been studied, their excellent mechanical properties, good swelling behavior and thermal stability being remarkable. In addition, in order to evaluate their possible applications as scaffolds or in wound healing applications, microsized fibers have been fabricated by electrospinning.