Polybenzoxazine-hazelnut shell composites: Curing behavior, thermal stability, mechanical properties, and material stress analysis

In this work, hazelnut shell (HS) particles were added to the bisphenol-A aniline-based benzoxazine (BA-a) matrix and micro-sized HS particles of varying weight percent (5%, 10%, 15%, 20%, 25%) were successfully blended with BA-a resin. The effects of reinforcing HS particles to the neat matrix were studied. The curing behavior, mechanical properties, and thermal degradation of the composites were performed using differential scanning calorimetry, tensile and impact tests, and thermogravimetric analysis. Glass transition temperature (T-g) was lowered to 16 degrees C which is 4% less than the neat matrix, increase in char yield (Y-c) was recorded in composites. Tensile and impact strength of the prepared composites was improved significantly. There was 82.6% increase in Young's modulus and 74.1% increase in the tensile stress for the BA-a/HS composite containing 25 wt% HS particles. Meanwhile, the impact strength of the composites was elevated, and a maximum of 207% increase in impact strength was observed without sacrificing other properties of the matrix. Additionally, finite element analysis was carried out on a cantilever beam designed in CATIA V5 with the properties of neat BA-a and HS filled composites. The stress analysis was observed on different HS filled composites, showing better results for HS filled composites as compared to neat polymer.

Automated summary

In this study, hazelnut shell particles were added to a bisphenol-A aniline-based benzoxazine matrix and their effects on the matrix properties were investigated. The results showed that the addition of hazelnut shell particles led to a decrease in glass transition temperature, an increase in char yield, and a significant improvement in tensile and impact strength of the composites. Finite element analysis also demonstrated better stress analysis results for the hazelnut shell filled composites.