Poly(β-pinene) as an efficient biobased tackifier for metallocene poly (ethylene) based hotmelt adhesives

In this work, poly(beta-pinene) was used for the first time as a biodegradable and renewable tackifier for hot melt adhesives (HMA) based on poly(ethylene) catalyzed by metallocenes (mPE). The HMA formulations were prepared using only poly(beta-pinene) as tackifier or using mixtures of the terpene with the hydrocarbon resin C5 ((poly(beta-pinene): C5: 80:20; 60:40; 50:50; 40:60; 20:80). An HMA formulation containing only C5 was also prepared for comparison purposes. The results of the thermal analysis showed that the addition of poly(beta-pinene) to the formulations increased their thermal stability as well as the value of melting temperature (T-m) and crystallization temperature (T-c). Dynamic mechanical thermal analysis (DMTA) showed that the formulation containing both tackifiers in a weight ratio of 50% had a higher degree of homogeneity compared to the other formulations. Regarding the mechanical properties, the results showed that the addition of higher amounts of poly(beta-pinene) resulted in stiffer materials. The values for modulus of elasticity, tensile strength, and elongation at break were similar to those obtained with poly(ethylene-co-vinyl acetate)-based HMA (EVA), the most commonly used HMA. Regarding viscosity, the results show that increasing amounts of poly (beta-pinene) increase the viscosity of the formulation. When both tackifiers are used in a weight ratio of 50%, the viscosity is very similar to the formulation with the C5 resin.

Automated summary

Poly(beta-pinene) was used as a tackifier in hot melt adhesives for the first time, improving thermal stability and crystallization properties of the formulations while increasing material homogeneity. Higher amounts of poly(beta-pinene) resulted in stiffer materials and increased viscosity in the formulations.