Synthesis and Swelling Behavior of Carrageenans-Graft-Poly(Sodium Acrylate)/Kaolin Superabsorbent Hydrogel Composites
In the present paper, a novel superabsorbent hydrogel composite based on carrageenan have been prepared via graft copolymerization of acrylic acid (AA) in the presence of kaolin powder using methylenebisacrylamide (MBA) as a crosslinking agent and ammonium persulfate (APS) as an initiator. The certain variables of the graft copolymerization (i.e. the monomer, the initiator and the crosslinker concentration as well as kaolin/carrageenan weight ratio) affected on the ultimate water-swelling capacity were optimized. The composite structure was confirmed using FTIR spectroscopy. A new absorption band at 1707 cm in the 1 composite spectrum confirmed kaolin-organic polymer linkage. The effect of kaolin amount and MBA concentration showed that with increasing of these parameters, the water absorbency of the superabsorbent composite was decreased. Because of their exceptional properties, i.e. anhydrogalactose units (13). The types of carrageenans biocompatibility, biodegradability, renewability and differ only in the position and number of ester sulfate non-toxicity, polysaccharides and proteins are the groups. Following a continuous research on modification main part of the natural-based superabsorbent of carrageenans (14), in this work, we attempt to hydrogels. The higher production cost and low gel synthesize and characterize new superabsorbent strength of these superabsorbents, however, restrict composites based on carrageenan in the presence of their application widely. To improve these limitations, kaolin particles. The preparation of the biopolymer-based inorganic compounds with low cost can be used. The superabsorbent composites can also improve the introduction of inorganic fillers to a polymer matrix mechanical properties of materials and can lower the cost increases its strength and stiffness properties. of the finished product compared with the synthetic Among inorganic compounds, special attention has counterparts as well as providing biodegradable been paid to clay minerals in the field of nanocomposites characteristics.
Effect of Different Preparation Methods on Crosslink density and Mechanical Properties of Carrageenan filled Natural Rubber (NR) Latex Films
Abstract This research discussed the influenced of different preparation methods of Carrageenan fillers as new natural biodegradable additives in Natural Rubber (NR) latex compound. NR latex compounds with addition of 2 phr Carrageenan fillers was prepared through normal pre-vulcanization method which the NR latex compound was subjected to 70oC denoted as Method 1. The preparation of NR latex compounds with 2 phr Carrageenan fillers without temperature is denoted as Method 2. The unfilled NR Latex films also was prepared as a control through Method 1. The crosslink density and mechanical properties of NR Latex films were investigated via swelling test and mechanical testing (tensile and tear) respectively. The swelling test results shows that Method 2 have highest crosslink density where the crosslink density and mechanical properties via Method 1 shows a decreased value. This may contribute from the hydration of carrageenan at temperature of 40oC-70oC. The experimental results indicate that the addition of carrageenan with elimination of pre-vulcanization step is mainly responsible for the enhancement of crosslink density and mechanical properties compared to Method 1. Method 2 gives higher crosslink density, tear strength and lower modulus as evaluated from the mechanical properties. Carrageenan can be added as natural filler in NR Latex films with gives better interaction between rubber matrix and fillers with softer NR latex films which required in NR latex products especially gloves.
Self-assembly of pyridinium-tailored anthracene amphiphiles into supramolecular hydrogels.
The mixing of a polyacid cross-linker with a pyridinium-functionalized anthracene amphiphile afforded a supramolecular hydrogel through a self-assembly process that was primarily driven by π-stacking and electrostatic interactions.