This paper investigates the effect of aluminum hydroxide (ATH) content on the free volume and surface recovery property of polydimethylsiloxane (PDMS)-based silicone rubber containing low-molecular-weight siloxanes. With increasing ratio of ATH up to 43.1 wt %, the concentration of cyclic siloxanes (D n 5 [(CH 3 ) 2 SiO] n , n 5 4-12) in the PDMS matrix increases remarkably, indicative of a spacing effect of ATH particles on the crosslinking of PDMS chains. When more ATH is added, the concentration of D 4 -D 12 began to decrease. PDMS network variation is verified by free volume size corresponding to s 3 in positron annihilation lifetime spectroscopy. The o-Ps intensity decreases linearly with ATH content. Data obtained from X-ray photoelectron spectroscopy suggest the surface recovery property is weakened by ATH. This process is dominated by the amount of free volume holes in the sample. V C 2017Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45803.

An effective method for controlling scale formation in circulating cooling water system is the use of scale inhibitors. A novel multi-functional scale inhibitor AA-APES-H 3 PO 3 terpolymer, was prepared by acrylic acid (AA), ammonium allylpolyethoxy sulfate (APES), and phosphorous acid (H 3 PO 3) and the structural properties were identified by Fourier transform infrared and 1 H-NMR. The inhibitory power of the terpolymer was determined by using a static scale inhibition method. The polymer's effectiveness on calcium scales was assessed by using X-ray diffractometer, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It is shown that AA-APES-H 3 PO 3 terpolymer exhibited an excellent ability to control the formation of CaCO 3 scale at a mole ratio of 2/1 (AA/APES) with an inhibition efficiency of 92.6% at a level of 8 mg L-1 , and at the same time, it maintained a superior efficiency even at increasing solution temperature, pH value, and Ca 2+ concentration. Compared with commercial inhibitors, the order of preventing the precipitation of calcium carbonate was AA-APES-H 3 PO 3 > EDTMP > HEDP > PESA > PAA. Also the terpolymer displayed a superior ability to prevent calcium phosphate with approximately 100% inhibition efficiency at the dosage of 6 mg L-1 .

The purpose of the paper is to provide a non-phosphorus and nitrogen free calcium phosphate inhibitor maleic anhydride-allyloxy polyethoxy carboxylate. The approach is that synthesized monomer allyloxy polyethoxy carboxylate from allyloxy polyethoxy ether and chloracetic acid, and then prepared maleic anhydride-allyloxy polyethoxy carboxylate by free radical polymerization. Structures of allyloxy polyethoxy carboxylate and maleic anhydride-allyloxy polyethoxy carboxylate were characterized through FT-IR and 1H-NMR. Influence of monomer mole ratio in maleic anhydride-allyloxy polyethoxy carboxylate and viscosity-average molecular weight of maleic anhydride-allyloxy polyethoxy carboxylate on its calcium phosphate inhibition performance was discussed. Calcium tolerance and calcium phosphate inhibition capability of maleic anhydride-allyloxy polyethoxy carboxylate was compared with the latest generation of calcium phosphate inhibitor maleic anhydride-ammonium allylpolyethoxy sulphate, and other two kinds of known inhibitor acrylic acid/2-hydroxypropyl acrylate and acrylic acid/acrylamido-2-methyl-1-propane sulfonic acid. As a result, monomer mole ratio and viscosity-average molecular weight has great impact on property of maleic anhydride-allyloxy polyethoxy carboxylate. Calcium tolerance and calcium phosphate inhibition of maleic anhydride-allyloxy polyethoxy carboxylate is similar to maleic anhydride-ammonium allylpolyethoxy sulphate. The results reveal that maleic anhydride-allyloxy polyethoxy carboxylate is an excellent green calcium phosphate inhibitor.

Silicone rubber is the outer dielectric material of the composite insulator used in high‐voltage transmission lines. A study of the microstructure evolution during corona discharge could provide a new understanding of catastrophic fracture in composite insulators. In this paper, the corona degradation process of silicone rubber is divided into three stages based on the data obtained by slow positron beam and electrochemical impedance spectroscopy. In stage I, the S parameter decreases slightly in the low‐energy range, suggesting a crosslinking process in the polymeric “skin,” and the silicone rubber holds its high value of resistance, Rpore. In stage II, the organic sample surface is gradually transformed into an inorganic one. Further cracking of the surface layer contributes to a dramatic increase in the sample porosity. At the beginning of water immersion, the Bode phase angle remains approximately goodbreakinfix−50∘ at low frequency, and a diffusion‐dependent Warburg impedance is observed. In stage III, a massive number of polar groups and inorganic particles are generated and the sample fails to repel water. The increase in the sample porosity is the main factor that leads to an ingress of water and failure of the material, while the generated polar groups are the secondary factor.

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Conformal parameterization for surfaces into various parameter domains is a fundamental task in computer graphics. Prior research on discrete Ricci flow provided us with promising inspirations from methods derived via Riemannian geometry, which is rigorous in theory and effective inpractice. In this paper, we propose a unified conformal parameterization approachfor turning triangle meshes into planar and spherical domains using discrete Calabi flow onpiecewise linear metric. We incorporate edge‐flipping surgery to guarantee convergence as well as other significant improvements including approximate Newton's method, optimal step‐lengths, priority embedding and boundary customizing, which achieve better performance and functionality with robustness and accuracy.

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