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Hydrophobic poly(ethylene terephthalate) (PET) was prepared by reactive blending of PET with double epoxy groups modified polysiloxane (diepsi) or multiepoxy groups modified polysiloxane (multiepsi). The structure of the modified PET was characterized by 1H NMR and intrinsic viscosity. The grafted ratio of diepsi and multiepsi was 1.3 and 0.03 wt%, respectively. With the introduction of diepsi and multiepsi to PET, the water contact angle of modified PET increased from 73° to a maximum of 106°, showing the good hydrophobicity of the modified PET. The samples of modified PET were washed with different solvents and their water contact angles did not significantly decrease, indicating good durability of the hydrophobicity. Moreover, the films of modified PET prepared by solution casting (phenol and 1, 1, 2, 2-tetrachloroethane mixed solution) showed excellent hydrophobicity with the contact angle 151°. Scanning electron microscopy images showed the surface of the modified PET films to be rougher than those o...

In the present study, we investigated the influences of polymerization and crosslinking technologies on the branched-chain structures, crystallization behaviors, and gel networks of two types of low-density polyethylenes, LDPE1 and LDPE2, polymerized under different polymerization conditions in commercial large-capacity production lines. High temperature 13C NMR analysis suggests that the molar contents of both long-chain branches and short-chain branches of LDPE2 were markedly higher than those of LDPE1 due to a higher polymerization temperature for LDPE2. The high content of chain branches of LDPE2 leads to its relatively higher storage modulus, entanglement density, and gel content, as indicated by dynamic mechanical analysis. In addition, when the crosslinking temperature reached 180°C, the LDPE2 crosslinked with 2 wt% dicumylperoxide (XLPE2-D2) displayed a relatively wider processing time window and a faster crosslinking rate than XLPE1-D2. Successive self-nucleation and annealing fractionation indic...