Effect of Amino and Glycidyl‐Based Coupling Agent on the Tensile and Adhesion of Hyperbranched Polymer/Silica/Epoxy Composites

ABSTRACT The cohesion of solder mask (SM) and adhesion between SM and copper pads are essential, especially for SM‐defined solder pads. In this study, the effect of the addition and loading (3, 5, 10 wt%) of silane coupling agents (SCAs) on the tensile and adhesion properties of hyperbranched polyester polyol/silica (HBP‐OH/SiO 2 )‐filled epoxy composite were investigated. 3‐aminopropyltriethoxysilane (APTES) and 3‐Glycidyloxypropyltrimethoxysilane (GPTMS) were added at 3, 5, and 10 wt% concentrations into HBP‐OH/SiO 2 /epoxy composites. The SCA‐added epoxy composites were fabricated by integral blending method using the ultrasonication technique and were spin‐coated onto copper clad laminate as substrate before thermal curing. Characterizations such as tensile test, pneumatic adhesion tensile testing instrument test, peel test, hydrolytic stability, and chemical stability tests were performed. Results demonstrated that the APTES‐added epoxy composite displayed higher tensile and pull‐off strength, where 5 wt% APTES showed an increase of tensile strength, tensile strain at break, and modulus by 5.58 MPa, 0.235%, 0.98 GPa, and 43.4%, respectively, as compared to the untreated sample. APTES‐added epoxy composites showed more cohesive failure than GPTMS‐based epoxy composites. This was evidenced by their higher percentage of cohesive failures and stronger adhesion to copper surfaces. Besides, 3 and 5 wt% GPTMS‐ and all APTES‐added specimens exhibited strong adhesion of 4B and above in the peel test. No surface defect was observed apart from the untreated specimen and the 10 wt% GPTMS‐added specimen in the chemical stability tests. In short, the 5 wt% APTES‐based HBP‐OH/SiO 2 /epoxy composite demonstrated the best tensile and adhesion properties among all composites.