Preparation and evaluation of composite microspheres of polyacrylamide‐grafted polysaccharides

Abstract

The poor mechanical strength and instability of polysaccharide's gel takes away opportunities for versatile application. The grafting of polyacrylamide (PAM) onto polysaccharide was found to be an efficient tool for transforming its properties and obtaining stable and robust composite microspheres (CMs). In this study, free-radical polymerization reaction was used for the grafting of PAM onto the polysaccharide backbone, and their hydrogel CMs were obtained through an ionotropic gelation method. Porous and buoyant CMs were obtained through the incorporation of sodium bicarbonate into the reaction mixture. Characterizations were done through Fourier transform infrared spectroscopy, thermal and scanning electron microscopy analysis. The mechanical strength and squeezing capacity were evaluated extensively through a modified syringe method developed in-house. The squeezing capacity of grafted CMs diminished with the formation of a complex interpenetrating network. The Young's modulus, swelling kinetics, mechanical strength, and squeezing capacity of the grafted microspheres were compared extensively.

Solid state grafting copolymerization of acrylamide onto poly(vinyl alcohol) initiated by redox system

“…Also, it was found from Table that the Young's modulus of grafted PVA films had an increase against the decease of the tensile strength with the increase of G p up to 53.8%, the reason for which could also be the hydrogen bonding between the branched PAM chain and the backbone PVA. The affecting factors behind this phenomenon possibly include molecular weight (both backbone and graft chain), grafting percentage, grafting density, chemical cross‐linking, or their combination. Young's modulus of a polymer is the initial response to stress, closely relative to interaction of polymer chains; while the tensile strength is mainly related to the molecular weight.…”

Melt-in-Mouth Multi-particulate System for the Treatment of ADHD: A Convenient Platform for Pediatric Use

“…Water was added dropwise on tissue paper (to make it wet) using a dropper and further moisture uptake behaviour by the pellet was observed under microscope at a magnification ×4 (22).…”

Electron-Catalyzed Aminocarbonylation: Synthesis of α,β-Unsaturated Amides from Alkenyl Iodides, CO, and Amines

“…The α,β-unsaturated amide motif is present in a wide range of natural products and represents an important building block for organic and materials syntheses, − as covered by several reviews. , Transition-metal-catalyzed carbonylations − of alkynes, − alkenes derivatives, − or alkenyl − (pseudo)-halides in the presence of amines provide numerous pathways to α,β-unsaturated amides (acrylamides). In contrast, alkenyl radical amino­carbonylation appears as a promising alternative for transition-metal-free synthesis of unsaturated amides. − In an example representative from our previous work, tributyltin can be used to achieve formal hydro-aminocarbonylation of alkynes (Scheme , eq 1).…”