Preparation, characterization and properties of liquid natural rubber with low non-rubber content via photodegradation

Photodegradation of natural rubber (NR) latex produced low molecular weight liquid natural rubber (LNR). During the photodegradation, organic materials particularly surfactants and non-rubbers also decomposed. The decomposition of surfactants and non-rubbers could influence the stability of the latex. Anionic and non-ionic surfactants were used to stabilize NR latex during the photodegradation. It was found that the anionic surfactant gave better resistance to oxidizing agent and UV radiation compared to the non-ionic surfactant. Hence, better stability of the NR latex was observed throughout the reaction. The zeta potential of NR latex increased during photodegradation due to the presence of negatively charged substances. The nitrogen content, which represents protein in NR decreased after photodegradation, whilst the phosphate content, which represents phospholipid head increased in the serum. This indicates the occurrence of decomposition of the non-rubber compounds in NR. The molecular weight of NR latex stabilized with anionic surfactant, sodium dodecyl sulphate, reduced from 544 × 10 to 19 × 10 g/mol after 48 h of reaction. SEM micrographs showed the latex particles of LNR were spherical and larger compared to NR. FTIR and NMR spectra confirmed the presence of telechelic hydroxyl and carbonyl groups, resulted from the chain cleavage.