Effect of interaction from the reaction of carboxyl/epoxy hyperbranched polyesters on properties of feedstocks for metal injection molding

Abstract

The purpose of this study is to improve the properties of the feedstocks and shape retention of debinded parts by the reaction between 17-4PH stainless steel powders. Carboxyl-terminated hyperbranched polyester (CTHP) and epoxy-terminated hyperbranched polyester (ETHP) were used to treat the powders, and termed as CTHP-m and ETHP-m with carboxyl and epoxy group, respectively. Comparing with pristine, CTHP-m and ETHP-m, feedstock prepared from equal amount of CTHP-m and ETHP-m (CTHP-m/ETHP-m) possessed more excellent properties. The experimental results showed that the critical solids loading, flexural modulus, density and melt flow index of CTHP-m/ETHP-m feedstock were 63.8 vol.%, 2800 Mpa, 5.06 g/cm3 and 62 g/10min, respectively, which were obviously higher than that of others. Also, the shape retention of CTHP-m/ETHP-m debinded parts was the best of all the samples. The improved properties of CTHP-m/ETHP-m feedstock were attributed to the powder interaction between CTHP-m and ETHP-m formed by the chemical reaction between epoxy and carboxyl group.

Effect of surface modification of metal powders (by aluminum stearate) on the properties of metal injection molding feedstock

“…The results show that the interaction between powders can improve the green density, and shape retention of the part after thermal debinding. Chen et al 15 modified the surface of 17-4PH powder by using hydroxy-terminated/carboxy-terminated/epoxy hyperbranched polyester, respectively, and studied the influence of the interaction between the modified powder and the functional binder on the feedstock properties. The results show that the feedstock had a higher critical powder loading, and the green parts had a higher density, mechanical strength, and shape retention, which indicate that the interaction between carboxyl/epoxy hyperbranched polyesters can enhance the properties of MIM feedstocks and the quality of the final products.…”

Preparation and research of epoxy modified by carboxyl-terminated polybutylene adipate at room temperature

“…can react with epoxy resin to improve the compatibility with resin matrix and improve the mechanical properties. 16,17 Up to now, the active end-group toughening agents mainly include carboxyl-terminated liquid nitrile rubber (CTBN), amino-terminated liquid nitrile rubber (ATBN), polysulde rubber and so on. [18][19][20][21] In general, rubber toughened epoxy resin is achieved by modulus loss and glass transition temperature reduction, but the glass transition temperature can be increased by adding other llers.…”