Study of chitosan and its derivatives as preservatives for field natural rubber latex

Abstract

In this study, the chitosan and its derivatives were tested for their preservative activities for field natural rubber (NR) latex. A series of chitosans with different molecular weights were obtained by nitrous acid depolymerization. The chemically modified chitosans, Ncarboxymethyl chitosan (NCMCh), N-sulfated chitosan (NSCh), and N-(2-hydroxy)propyl-3-trimethylammonium chitosan chloride (NHTACh), were prepared from high and low-molecular weight chitosans. Preservative activities for field NR latex of these chitosans were investigated based on the measurement of volatile fatty acids (VFA) number of the treated latex. The preservative activities of chitosan increased with decreasing molecular weights. The lowmolecular weight NSCh and NHTACh exhibited good preservative activity for the latex. By the use of low-molecular weight NHTACh in combination with octylphenol poly (ethyleneglycolether) (Nonidet P40), the latex was successfully preserved for more than 1 month in the low-ammonia condition. The results showed an attractive feature to develop the preservative system, which was possible to reduce the concentrations of ammonia and carcinogenic nitrosamine in the NR latex.

Impact of N,N ′ -Methylene-bis-Morpholine on the Preservation of Natural Rubber Latex

“…Bacteria and enzyme degra-dation products will destroy the protective coating of NRL particles, reducing their stability [6,7]. Furthermore, the formation of fatty acids, which neutralize alkaline substances and decrease pH value [8], reduces particle repulsion [9][10][11], resulting in adhesion and aggregation development between rubber particles. Furthermore, it can reduce latex colloid stability, causing fast solidification and rot of NRL [12,13].…”

The use of 1,2-benzisothiazolin-3-one (BIT) in preparation of low-ammonia and zinc-free natural rubber latex concentrate

“…Several studies reported the development of the various preservatives systems that could inhibit the activity of bacteria in the latex and retard the chemical reaction of multivalent metal ions [8,9]; however, it suffered from certain disadvantages such as a gradual fall in the pH of the latex when stored for over a long period. Formaldehyde-based preservatives latex thickens with age and thus becomes unmanageable.…”

Structure and Performance of Carboxylic Styrene Butadiene Rubber/Citric Acid Composite Films

“…Nie et al fabricated a continuous framework network of CMCs, which endowed epoxidized NR (ENR) with better mechanical properties and conductive ability when the moisture content was higher than 1%. Loykulnant et al prepared antibacterial NR composites with chitosan. However, it is noteworthy that the aforementioned natural polymers have relatively longer chains, whose common interactions such as twisting and folding of the macromolecular chains shield every part of reactive groups in the solid state.…”