An oxidative aging‐viscoelastic constitutive model was established to study the coupled heterogeneous oxidation and viscoelastic performance of rubber during aging process. The basic elasticity and viscoelasticity of rubber materials were comparatively considered as the function of ongoing aging. The dynamic compression process of natural rubber at different aging times was analyzed by the finite element method. And then the effects of oxygen uptake, diffusion, and oxidative reactions on the dynamic viscoelasticity of rubber were analyzed. The permeability of the oxygen in natural rubber was determined by means of molecular dynamics simulation. The results reveal that the heterogeneous degradation caused by diffusion‐limited oxidation can lead to a complex stress distribution in the natural rubber specimen under dynamic loading condition; the relaxation time and the energy dissipation of the rubber specimen also increased after aging. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47452

To develop an absorbent with high removal rate and adsorptivity for low‐concentration formaldehyde (FA) gas, amino‐decorated viscose‐based activated carbon fiber (VACF‐N) was synthesized by ethylenediamine (EDA) grafting process on the surface of viscose‐based activated carbon fiber (VACF). A simulated static adsorption of low‐concentration FA gas in a confined space was used as research target. For 2.45 and 8.15 ppm of FA gas, both the FA removal rate and the adsorptivity of VACF‐N were enhanced significantly after the EDA grafting process. The maximum of FA adsorptivity was 0.59 mg/g (1.92 times that of pristine VACF) for 2.45 ppm FA gases and 1.17 mg/g for 8.15 ppm FA gases. In particular, FA removal rate reached 100 % in only 28 minutes under the static adsorption of 2.45 ppm of FA gas. Predictably, VACF‐N has wide application prospects in the field of low‐concentration FA gas purification in a confined space.

Crystal structure and amorphous carbon of viscose-based activated carbon fiber (VACF) also have a close correlation with the formation of pore structure, thereafter dominating sorption capacities and mechanisms. In this paper, a novel phosphoric acid reactivation process assisted by sonication is proposed to modify VACF. Analysis results indicate that the application of sonication in phosphoric acid reactivation process can significantly improve the activation effect. After treating by the novel reactivation process, its micropore volume increased by 38.93%, mesopore volume increased by 676.56% and specific surface area increased by 53.45%. Moreover, the effect of the novel reactivation process on its crystal structure is to promote microcrystal growth and increase the disorder degree of crystal structure. Moreover, the simultaneous increase of micropore and mesopore is related to the decrease of amorphous carbon and the densifying of microcrystal structure.