Use of Liquidambar Orientalis Mills in natural rubber compounds as an alternative to synthetic resins

Phenolic resins are useful additives that provide various functions for rubber compounds during compounding and vulcanization, as well as after cure. Natural resins are considered as strong alternatives to synthetic ones due to environmental concern. Liquidambar Orientalis Mills is an endemic plant and grows in many different geographies including Turkey. In this study, the phenolic resin obtained from Liquidambar Orientalis Mills has been studied regarding its functions in a generic natural rubber compound. It was incorporated into the rubber compound with and without selected gum and phenolic resins so that mainly obtaining competitive adhesion properties. Both individual and collaborative effects of the natural resin were evaluated. Rheological, thermal, morphological, mechanical and adhesion properties of the compounds were studied comparatively along with the non-linear cure kinetics. Liquidambar Orientalis Mills has been found to be a good alternative to both gum and phenolic resins in rubber compounds. Besides, significant improvement could be achieved for particularly rubber–steel adhesion.