In the present study, acrylonitrile–butadiene–styrene (ABS) terpolymers were investigated. ABS micro-foaming was widely developed in the literature because of the ease of processing of ABS and its good mechanical properties [12] and [15]. Moreover, the presence of the rubbery phase of butadiene dispersed into a rigid matrix of acrylonitrile/styrene can be key for improving the nucleation rate and cell density, by creating heterogeneous nucleation, with dispersed phase as nucleation agent. Indeed, the presence of a heterogeneous nano-structure possibly causes an increase in the number of nucleating sites by decreasing the value of Gibbs free energy of nucleation [16]. With a “low pressure” process, Murray et al. [15] produced an ABS foam with a cell density of 1.4 × 1013 cm−3 and an average cell size of 0.5 μm. Carrying out a similar foaming process, Nawaby et al. [17] also obtained ABS foams with an average cell size of 0.5 μm and a foam density of 0.2 g cm−3 by working with low saturation temperature (less than 30 °C). However, even though nano-cellular foams with low density were produced, their cell size remains too high to access the relevant thermal insulation properties with such materials.
In this paper, we focus on the foaming of ABS terpolymers, with a batch process, using a low saturation pressure. Different ABS microstructures were investigated to modify heterogeneous nucleation mechanisms during the foaming stage in order to obtain different final foam structures. The influence of foaming conditions on the foam morphologies is also presented and discussed.
In the present study, acrylonitrile–butadiene–styrene (ABS) terpolymers were investigated. ABS micro-foaming was widely developed in the literature because of the ease of processing of ABS and its good mechanical properties [12] and [15]. Moreover, the presence of the rubbery phase of butadiene dispersed into a rigid matrix of acrylonitrile/styrene can be key for improving the nucleation rate and cell density, by creating heterogeneous nucleation, with dispersed phase as nucleation agent. Indeed, the presence of a heterogeneous nano-structure possibly causes an increase in the number of nucleating sites by decreasing the value of Gibbs free energy of nucleation [16]. With a “low pressure” process, Murray et al. [15] produced an ABS foam with a cell density of 1.4 × 1013 cm−3 and an average cell size of 0.5 μm. Carrying out a similar foaming process, Nawaby et al. [17] also obtained ABS foams with an average cell size of 0.5 μm and a foam density of 0.2 g cm−3 by working with low saturation temperature (less than 30 °C). However, even though nano-cellular foams with low density were produced, their cell size remains too high to access the relevant thermal insulation properties with such materials.In this paper, we focus on the foaming of ABS terpolymers, with a batch process, using a low saturation pressure. Different ABS microstructures were investigated to modify heterogeneous nucleation mechanisms during the foaming stage in order to obtain different final foam structures. The influence of foaming conditions on the foam morphologies is also presented and discussed.
การแปล กรุณารอสักครู่..
