In recent years, the treatment of water pollution has been a challenging and far-reaching topic. In order to improve the adsorption performance of polyvinyl alcohol nanofibers, a new nano-adsorbent graphene oxide was introduced into them in this work. The introduction of GO greatly increases the adsorption of Cu2+, Methylene blue (MB) and Congo Red (CR). The adsorption kinetics and isotherm analysis of the PVA/GO nanofiber film during the adsorption process showed that the adsorption of Cu2+ and MB by PVA/GO nanofiber film was mainly chemical adsorption, while the adsorption of CR was mainly physical adsorption. The adsorption process of PVA/GO nanofiber film on Cu2+ was in line with the Langmuir isothermal adsorption model, that is, single molecular layer adsorption, the distribution of adsorption active sites was relatively uniform, and the increasing temperature was more conducive to the adsorption of Cu2+.
Slow crack growth (SCG) is the principal factor for determining the operating lifetime of polyethylene (PE) pipes. Exploring the relationship between the molecular structure and the strain hardening (SH) modulus is helpful to evaluate the SCG resistance of PE pipe materials accurately. This paper uses an efficient SH test method to study the SH modulus for four kinds of PE pipes. Meanwhile, the correlation between SH modulus and sample thickness, material crystallinity (X c ), comonomer type and content, weight-average molecular weight, and molecular weight distribution has been established and investigated respectively. The results represent that the comonomer type and the X c of PE materials played significant roles in the SH modulus. The SH modulus of ethylene-hexene copolymer is 5-7 MPa higher than that of ethylene-butene copolymer. The amount in the range of 1 Â 10 3 to 1 Â 10 5 of the molecular weight distribution of PE materials has a significant contribution to the establishment of the tie molecular network. In addition, the higher X c and the thinner thickness were beneficial to obtain the higher measured SH modulus.
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