The crystalline structure evolution of poly(vinylidene fluoride) (PVDF) during tensile deformation at 60 °C, 140 °C and 160 °C, i.e. between the glass transition temperature (T_g) and the melting temperature (T_m), was investigated by in-situ synchrotron SAXS and WAXS techniques. The analysis of the obtained scattering results indicated either yielding or α–β transformation in PVDF occurred and initiated at almost the same strain level with different stretching temperatures. A deformation mechanism was proposed for PVDF to illustrate the structure evolution during uniaxial stretching at high temperature indicating that the initial crystallite and crystalline lamellae structures of stretched PVDF are destroyed and orientated not simultaneously, which is intimately related to the yield point and the initial of α–β transformation on a certain degree of orientation. The long period along tensile direction increases to a maximum and then drops into a lower but stable value during this stage of deformation.

The mechanical properties of polymers are not only determined by their structures, but also related to the temperature field in which they are located. The yield behaviors, Young's modulus and structures of injection-molded poly(lactic acid) (PLA) samples after annealing at different temperatures were measured during stretching within 30–150 °C. The in situ photographs were recorded with a camera to observe deformation behavior during stretching. The less ordered α′ form crystal of PLA can be formed in the un-annealed PLA samples and those that were annealed at 70 °C with low crystallinity. The crystallinity increases with increasing annealing temperature and α form crystal is formed when the annealing temperature is higher than 100 °C. The stretched samples with low crystallinity show the first yield at draw temperatures below the glass transition temperature (T_g) and the second yield above T_g. For the samples annealed between 80 and 120 °C, a peculiar double yield appears when stretched within 50–60 °C and only the first or the second yield can be found at the lower and higher draw temperatures. The yield strain and yield stress together with Young's modulus were obtained and discussed in terms of the effects of the draw temperature and crystalline structure of PLA samples.

A series of organo-soluble gold nanoparticles (AuNPs) were prepared through the reduction of HAuCl₄ by NaBH₄ in the presence of amphiphilic hyperbranched copolymers bearing a hydrophilic hyperbranched polyethylenimine (PEI) core and a hydrophobic dendritic shell. For comparison, the corresponding analogues with a PEI core and a linear shell were also used to prepare the organo-soluble AuNPs. All the obtained AuNPs were characterized by transmission electron microscopy. It was found that under a high feed ratio of polymer to HAuCl₄, the average diameter of the obtained small AuNPs was similar, and was independent of the shell morphology of the hyperbranched polymeric stabilizers. Reducing the feed ratio of polymer to HAuCl₄ led to the formation of larger AuNPs and irregularly shaped AuNP aggregates. The stability evaluation on the basis of two-month shelf-storage demonstrated that the obtained AuNPs were stable under shelf-storage regardless of whether the shell of the hyperbranched polymeric stabilizer was dendritic or linear. These organo-soluble AuNPs could be used as efficient catalysts for the biphasic catalytic reduction of 4-nitrophenol by NaBH₄, and could also be conveniently recovered and reused. The stabilizers with a dendritic shell endowed the AuNP catalyst with a higher performance than the corresponding stabilizers with a linear shell, including: (1) a higher catalytic rate; (2) the ability to be recovered and reused more times; (3) a maximal turnover number of around 23 000, which is unprecedented in the catalytic reduction of 4-nitrophenol.