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

Abstract

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.

Exploring the Effect of Resins of Different Origin on the Structure, Dynamics and Curing Characteristics of SBR Compounds

“…A similar trend is observed for the optimal cure time ( t C90 ). The increase in t S2 observed in the presence of Kristalex can be attributed to the physical adsorption of curatives onto the resin particles [ 24 , 25 , 35 ]. Conversely, the reduction in t S2 induced by SMD and Dertoline is compatible with the fact that these resins contain functional groups capable of accelerating the reaction between accelerators, activators, and sulfur in the early stages of curing [ 21 , 25 , 52 ].…”

“…The lower M L values obtained for the resin-containing samples indicate that, at the vulcanization temperature, which is higher than the resin’s T g ( Table 3 ), all the resins act as plasticizers, effectively decreasing the viscosity of the rubber matrix. This improves the compound’s processability and serves as an initial indication of good compatibility between the resin and SBR [ 1 , 24 ]. On the other hand, the decrease in M with the addition of resin suggests a diminished crosslinking efficiency.…”

“…Improving the “magic triangle” is now even more challenging due to the requirements imposed by the green transition. Indeed, in recent years, substituting synthetic and petroleum-based ingredients with renewable and more eco-friendly alternatives has emerged as an imperative concern to reduce the environmental footprint in rubber manufacturing [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ]. In this frame, resins derived from plant sources have been proposed as multifunctional additives for rubber compounds [ 21 , 22 , 23 , 24 , 25 ], and their influence on macroscopic features, such as curing characteristics, rheological, mechanical, and adhesive properties, has been investigated.…”

“…Improving the "magic triangle" is now even more challenging due to the requirements imposed by the green transition. Indeed, in recent years, substituting synthetic and petroleum-based ingredients with renewable and more eco-friendly alternatives has emerged as an imperative concern to reduce the environmental footprint in rubber manufacturing [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. In this frame, resins derived from plant sources have been proposed…”

“…Polymers 2024, 16, 834 2 of 17 as multifunctional additives for rubber compounds [21][22][23][24][25], and their influence on macroscopic features, such as curing characteristics, rheological, mechanical, and adhesive properties, has been investigated. On the other hand, little attention has been paid so far to the changes occurring at the "microscopic" level.…”