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How politics influences firm behaviours and economic outcomes is a longstanding question in research and public debate. One important way in which politics is conjectured to influence real decisions is through the channel of uncertainty. While extensive prior studies focus on the impact of political uncertainty on firms’ investment and financing activities, the evidence on how political uncertainty affects firms’ operating decisions remains scarce. To fill this gap in the literature, this study investigates the impact of political uncertainty on asymmetric cost behaviour (i.e. cost stickiness) for listed firms in China. Using the turnover of prefecture-city officials as a measure of exogenous fluctuations in political uncertainty, we find that political turnover leads to a higher degree of cost stickiness, implying that firms retain slack resources when political uncertainty is high. Moreover, the effect of political uncertainty on cost stickiness is more pronounced for firms residing in regions with weak institutional environment, firms that are privately owned and with small size, and when the newly appointed official is from a different city. Our findings suggest that political uncertainty is an important channel through which the local political process influences corporate operational decisions, thus firms should take political uncertainty into account when setting their resource adjustment policies.

In order to protect the articles in buildings from ultraviolet radiation and save air-conditioning energy, polyvinyl butyral laminated glass are employed and produced in large quantities. Several inorganic particles with blocking effect have been doped into PVB, such as TiO2, ZnO, and ATO. T-ZnOw is a widely used functional structural material with excellent absorption properties. Herein, T-ZnOw was lipophilic modified with silane coupling agent KH-570, and T-ZnOw/PVB composite films were prepared via subsequent solution blending. As per the FTIR spectrum, a characteristic peak of Si–O–Zn at 1165 cm−1 was observed, indicating that T-ZnOw was successfully modified by KH-570. T-ZnOw before and after modification was separately mixed with the St/H2O mixed solution. The modified T-ZnOw could be dispersed in styrene instead of water, displaying a certain lipophilicity. On the other hand, from a microscopic perspective, the SEM images suggest that filling the filler in the form of a suspension can disperse the modified T-ZnOw in PVB in an independent four-needle form, which contributes toward improvement of the agglomeration of T-ZnOw in the PVB matrix. The UV–Vis–NIR spectrum shows that the addition of T-ZnOw reduced the UV transmittance of T-ZnOw/PVB composite films from 50.84 to 25.77%, resulting in a decrease in near-infrared transmittance from 82.14 to 43.22%. The ultraviolet and near-infrared light barrier properties of composite films were more than twice that of the ordinary PVB films. Moreover, the modified T-ZnOw endowed composite films with stronger ultraviolet light and near-infrared light-blocking properties, or better visible light transmittance. And the falling ball impact test proved that there was no clear relationship between the thickness of the film and the adhesion. This work proposes a new solution and preparation method for the production of energy-saving glass. Therefore, it is expected that using composite films instead of traditional PVB films to make laminated glass can greatly contribute toward energy conservation and environmental protection.

Methyl methacrylate-co-glycidyl methacrylate copolymers (MMA-co-GMA) were prepared to compatibilize the poly(butylene terephthalate) (PBT) and polycarbonate (PC) blends. The chemical reactions between the PBT and the epoxy groups and the good miscibility between the PC and the poly(methyl methacrylate) (PMMA) phase were responsible for the excellent compatibilization effect of the MMA-co-GMA copolymers. The MMA-co-GMA copolymers decreased the melting and crystallization temperature of the PBT phase in the PBT/PC blends. Dynamic mechanical analysis result showed that the exchange reactions were inhibited due to the compatibilization reactions owing to the consumption of the carboxyl/hydroxyl end groups of the PBT phase. MMA-co-GMA copolymers decreased the phase domain size of the PBT/PC blends, and with the increase in GMA content in the MMA-co-GMA copolymers, the blends changed from a double continuous phase to a single continuous phase structure. Tensile test indicated that the yield stress, elongation at break and elastic modulus of the PBT/PC blends increased due to the addition of MMA-co-GMA. The impact strength of the blends changed unnoticeably.

Maleic anhydride functionalized acrylonitrile-butadiene-styrene copolymer (ABS-g-MA) was used as an impact modifier of polyamide 6 (PA6). Epoxy resin was introduced into PA6/ABS-g-MA blends to further improve their properties. Notched Izod impact tests showed that the impact strength of PA6/ABS-g-MA could be improved from 253 to 800 J/m with the addition of epoxy resin when the ABS-g-MA content was set at 25 wt %. Differential scanning calorimetry results showed that the addition of epoxy resin made the crystallization temperature and melting temperature shift to lower temperatures; this indicated the decrease in the PA6 crystallization ability. Dynamic mechanical analysis testing showed that the addition of epoxy resin induced the glass-transition temperature of PA6 and the styrene-co-acrylonitrile copolymer phase to shift to higher temperatures due to the chemical reactions between PA6, ABS-g-MA, and epoxy resin. The scanning electron microscopy results indicated that the ABS-g-MA copolymer dispersed into the PA6 matrix uniformly and that the phase morphology of the PA6/ABS-g-MA blends did not change with the addition of the epoxy resin. Transmission electron microscopy showed that the epoxy resin did not change the deformation mechanisms of the PA6/ABS-g-MA blends. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 121: 909-915, 2011

Waterborne polyurethane (WPU) dispersions with a high solid content and low viscosity were prepared successfully by a two-step polymerization with isophorone diisocyanate, poly(propylene glycol), and dimethylol propionic acid as the main raw materials. The molar ratio of hard segments to soft segments was controlled to investigate its influence on the particle size, particle morphology, stability of dispersions, and final properties of the WPU films. Measurements including attenuated total reflectance/Fourier transform infrared spectroscopy, transmission electron microscopy, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction, polarizing optical microscopy, and contact angle tests were used to characterize the bulk structures, phase separation, thermal stability, crystallinity, and wettability of the WPU dispersions. The results indicate that all of the WPU dispersions with a high solid content (ca. 40 wt %) and low viscosity (ca. 20–50 mPa s) displayed excellent stability. The prepared WPU dispersions with acetone contents of 5–7 wt % could be used directly as an ink binder without removing the acetone; this is beneficial to industrial applications of water-based ink binders. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2017

Middle molecular weight epoxy resin was used to modify the properties of polybutylene terephthalate (PBT) and glycidyl methacrylate-functionalized acrylonitrile-butadiene-styrene (ABS-gGMA) blends. Rheological tests showed that the complex viscosity and storage modulus of PBT increased with the addition of epoxy resin due to the chemical reactions. PBT displayed nonNewtanian fluid behaviour when epoxy resin content was 10wt% or higher. SEM results showed there was no obvious difference between the morphology of PBT/ABS-g-GMA blends when epoxy resin content was low, however, agglomeration of ABS phase took place when epoxy resin content was 10wt% or higher due to the complicated reactions. DSC results showed that the addition of epoxy resin to PBT/ABS-g-GMA blends improved the compatibility according to Tm depression criterion and DMA test further testified the improved compatibility. Mechanical tests showed impact strength of 902J/m and yield strength of 42MPa was achieved when 20wt% ABS-g-GMA and 5wt% epoxy resin were used, which displayed supper-toughness and much stiffer properties. Introduction Blends of polybutylene terephthalate (PBT) and acrylonitrile-butadiene-styrene (ABS) are of both scientific and commercial interests because of they inherit superior combination of impact strength, modulus, heat, chemical and abrasion resistance from their homopolymers [1]. PBT/ABS blends with super-toughness property can be achieved with a proper choice of materials and processing conditions even without use of any compatibilizers [2, 3]. On the other hand, reactive compatibilization using in situ reactive copolymers have more often been utilized to prepare PBT/ABS blends. In these studies compatibilizers were focused on the epoxy–functionalized copolymers [4-10], such as styrene-acrylonitrile-glycidyl methacrylate (SAG) and methyl methacrylate-glycidyl methacrylate-ethyl acrylate (MGE) copolymers. These copolymers contain epoxy groups that can react with PBT end groups (-COOH or – OH) to form block or graft copolymers at the matrix/dispersed phase interface through in situ reactions. This process reduces the interfacial tension between the blend components and retards dispersed phase coalescence via steric stabilization [11-14]. In PBT/ABS blends, the influence of ABS properties (such as ABS content, core-shell ratio, AN content and grafting degree), dispersed phase morphology, compatibilizer * Correspondence to: Huixuan Zhang (E-mail: zhanghx@mail.ccut.edu.cn)