Studies on N-methylene phosphonic chitosan

Effect of Modified Natural Filler O-Methylene Phosphonic κ-Carrageenan on Chitosan-Based Polymer Electrolytes

The potential for using O-methylene phosphonic κ-carrageenan (OMPk) as a filler in the chitosan-based polymer electrolyte N-methylene phosphonic chitosan (NMPC) was investigated. OMPk, a derivative of κ-carrageenan, was synthesized via phosphorylation and characterized using infrared spectroscopy (IR) and nuclear magnetic resonance (NMR). Both the IR and NMR results confirmed the phosphorylation of the parent carrageenan. The solid polymer electrolyte (SPE)-based NMPC was prepared by solution casting with different weight percentages of OMPk ranging from 2 to 8 wt %. The tensile strength of the polymer membrane increased from 18.02 to 38.95 MPa as the amount of OMPk increased to 6 wt %. However, the increase in the ionic conductivity did not match the increase in the tensile strength. The highest ionic conductivity was achieved with 4 wt % OMPk, which resulted in 1.43 × 10−5 Scm−1. The κ-carrageenan-based OMPk filler strengthened the SPE while maintaining an acceptable level of ionic conductivity.

Cellular behavior of L929 and MG-63 cells cultured on electrospun nanofibers of chitosan with different degrees of phosphorylation

Phosphate groups chemically grafted onto polymer substrates can be used as biomimetic analogs for in vitro studying of function of biomacromolecules and also as tissue substitutes in clinical conditions of organ loss. Despite this inspiration, studies correlating effect of degree of phosphate grafting of a polymer on fabrication and biological properties of polymers are lacking. In this work, N-methylene phosphonic chitosan (PC) with different degrees of phosphate contents were synthesized and the effect of phosphate grafting on electrospinning behavior of substituted polymers is investigated. In PC, higher phosphate content widened concentration range for nanofiber formation. Balance between conductivity and viscosity of solutions played a determinant role in the success of electrospinning process. Culture of L929 cells showed grafting-dependent increase in cell proliferation. On the other hand, culture of MG-63 cells showed a positive correlation between grafting degree and Alkaline Phosphatase (ALP) expression. It is concluded that improvement of cell response parameters of nanofiber scaffolds can be attained as a function of controlled degree of phosphate grafting in polymeric biomaterials with implications for bone tissue engineering applications. Such studies may also be useful to develop quantitative structure activity relationships of functional polymers.

Phosphorylation of bio-based compounds: the state of the art

The aim of this review is to present both fundamental and applied research on the phosphorylation of renewable resources, through reactions on naturally occurring functions, and their use in biobased polymer chemistry and applications.

Physico-chemical studies and emulsifying properties of N-propyl-N-methylene phosphonic chitosan

Chitosan is a modified, natural carbohydrate polymer derived by deacetylation of chitin. Due to the presence of two functional groups can undergo many chemical modifications. In a previous work we described the synthetic strategy and characterization of a novel soluble derivative: N-propyl-N-methylene phosphonic chitosan (PNMPC). In the study of some physicochemical properties, results showed that this modified chitosan aggregates in several steps when the concentration is increased. By addition of NaOH the initially coiled molecules stretch exposing more phosphonic acid groups to neutralization and finally give a cooperative reaction with OH((). PNMPC has emulsifying properties and gives O/W emulsions with quasi-monodisperse small droplets. Emulsions with 0.18% PNMPC and 30:70 o:w ratio exhibited the best emulsifying properties within the test range. This emulsion ratio showed high stability to long time storage and several successive freeze/thaw and heating/cooling cycles.