Abstract
Abstract
For the high content of carrageenan in some seaweed and the low cost and easy availability of semi refined carrageenan (SRC), SRC resin powder was selected as our research object. Due to its water solubility, a solution casting method was adopted to form film, hoping to prepare food packaging materials that partially replace petroleum based resin. The pure SRC resin casting film is very brittle and cannot be formed. Therefore, 40wt% glycerol was added to the formula to plasticize and improve the flexibility and demoulding ability of SRC. The plasticized SRC film still has limitations. Soluble petroleum based polymer poly(vinyl alcohol) (PVA) resin was used as a blending modifier, cinnamaldehyde (CIN) as a crosslinking agent for acetal reaction with hydroxyl groups, boric acid (BA) as a provider of acidic environment and an auxiliary agent for generating partial hydrogen bonds with hydroxyl groups. Eight experimental research formulas were designed and FTIR, XRD, thermodynamic properties and mechanical properties of the modified films were analyzed. Both microscopic and macroscopic analyses have shown that under the acidic conditions of BA, CIN undergoes an acetal reaction with SRC and PVA, therefore mass ratio of the formula that SRC/glycerol/PVA/CIN/BA is 100/40/33.3/10/10, the film has the best tensile strength of 34.85Mpa, higher than that of other films. It has been proven that CIN does indeed act as a crosslinking agent in the formula, forming a network structure that enhances it.