Advanced Materials Research Vols. 87-88

Abstract: Spinning and finishing techniques of a durable softening and water-repellent PP/HDPE heat-bondable fiber were introduced. The fiber has a core-sheath structure. PP is the core and HDPE is the sheath. The core-sheath fiber structure and spinning materials properties make the fiber have a good heat-bonding performance. During the finishing process the fiber got a durable softening and water-repellent quality by the durable waterproofing agent—a mixture of PMHS and PDMS. Experiments show that the fibers begin to melt and bond each other at 127.5°C and could keep a good water-repellent performance after being washed five circles.

Abstract: A series of aromatic hyperbranched polyethers have been synthesized from cyanuric chloride and diols by using nucleophilic displacement polymerization technique. The synthesized sulfur containing polyether was blended with commercially available low density polyethylene (LDPE) and plasticized poly(vinyl chloride) separately to improve the flame retardant property of those linear polymers. The flame retardancy of blends at different dose levels of the hyperbranched polyether with those linear polymers was investigated by measurement of limiting oxygen index (LOI) value and thermogravimetric analysis. The LOI values and TG analysis of these blends indicated that the hyperbranched polyether act as flame retardant additive.

Abstract: The structure of rotors is an important factor, which impacts the quality of the mixed rubber. For the short fiber-rubber composite material, the structure of the rotors is most important. Through the experiments study, the mixing performances of four-wing synchronous rotor, six-wing synchronous rotor and new type of six-wing synchronous varying clearance rotor have been studied. The experimental results indicated that the mixing performance of the new type rotor is much better than the four-wing and six-wing synchronous rotor for the mixing of short fiber-rubber composite materials.

Abstract: Flame retardant nanocomposites were synthesized by melt-blending phosphorus-containing copolymer (PET-co-DDP) with multi-wall carbon nanotubes. PET-co-DDP was copolymerized with terephthalic acid (TPA), ethylene glycol (EG) and 9, 10-dihydro-10[2, 3-di-(hydroxy carbonyl)propyl]-10-phosphaphenanthrene-10-oxide (DDP). The structure of the nanocomposites was characterized by scan electron microscopy (SEM). Fire property measurements by cone calorimeter revealed that the incorporation of multi wall carbon nanotubes into PET-co-DDP significantly reduced the peak heat release rates compared with the PET-co-DDP. The thermal properties of the nanocomposites were investigated by thermogravimetric analysis (TGA). It was found that the thermal stability of copolyester was improved by the addition of the multi-wall carbon nanotubes. Char formation is the main factor for these improvements. The flame retardant performance was achieved through the formation of a relatively uniform network-structured floccule layer covering the entire sample surface without any cracks or gaps. This layer re-emitted much of the incident radiation back into the gas phase from its hot surface.

Abstract: The changes of temperature in the rubber mixing process is of great significance. How to ensure the changes of temperature in rubber mixing is an important issue. The article introduces the temperature control system based on the fuzzy control algorithm. Using the host computer as the fuzzy controller, and the host computer educes the control value based on the difference between the reference input and the measure value. The system automatically discharges of high temperature water and automatically adds the appropriate amount of cooling water. The system can ensure the stability of the mixing temperature and ensure the quality of rubber mixing.

Abstract: The curing behaviour of an epoxy/nmSiO2 nanocomposites system composed of a bifunctional epoxy resin with an anhydride curing agent and nmSiO2 was investigated. Differential scanning calorimetry (DSC) was used to investigate the curing behaviour of the nanocomposites system. As for the nanocomposites system containing different amount of nmSiO2, the values of activation energy, reaction order, theoretic gelling temperature and theoretic curing temperature were evaluated by kinetic equations. And the effect of nmSiO2 on the curing reaction and the curing reaction mechanism of the system were discussed. The results showed that the curing rate of the nanocomposites system increased slightly with adaptively increasing nmSiO2 content, and the curing process is at 110°C for 1hr, 150°C for 2hr.

Abstract: Conductive polyaniline (PANI) was synthesized by the oxidation of aniline with complex oxidant composed of ammonium persulfate ((NH4)2S2O8) and ascorbic acid (C6H8O6) in a reaction media containing sulfuric acid (H2SO4). The effects of concentration of H2SO4, (NH4)2S2O8 and (NH4)2S2O8/C6H8O6 mol ratio on the polymerization of aniline were studied. The optimal polymerization condition was aniline 1mol/L, H2SO4 1mol/L, and compound oxidant (mole ratio of (NH4)2S2O8 to C6H8O6 as to 10:1) 1mol/L at room temperature without the protection of N2. The conductivity and yield of PANI reach 13.3S/cm and 96.7%, respectively. The structural changes of PANI were measured by FTIR, Raman and XRD. The results indicated that PANI was some crystal and its groups took place red shift.

Abstract: The light guide plate is an important element of the LCD backlight module which demands a certain degree of transparency and uniformity of gray. The defects such as black spots and yellow surface appeared when the light guide plate was processed by domestic equipments. The main problem was caused by the plasticization unit. The Influencing factors of performance for polycarbonate (PC) special screw were discussed in this paper. The conveyance capacity of melt in the metering zone of injection screws with different flight width and channel depth was analyzed by POLYFLOW software. In order to obtain high surface hardness, corrosion resistance and smoothness of PC special screw, surface coating processing was the key point for injection molding light guide plate. Moreover, the peel strength of PC with different coating processing metallic block was tested and measured. he experimental results of the analysis showed that the nickel-tungsten alloy plating and physical vapor deposition can significantly improve stripping properties, corrosion resistance and smoothness. The influencing factors of coating and PC materials’ stripping were analyzed. Through industrial testing, the defective rate of light guide plate had been greatly reduced with physical vapor deposition compared to the screw with hard chromium plating.

Abstract: Doped polyaniline (PANI) was synthesized by chemical oxidative polymerization of aniline in aqueous acidic medium with mixed sulfuric acid and 5-sulfosalcyclic acid as complex dopant , and ammonium peroxydisulfate as an oxidant, and heat treated at 150°C, 200°C, 250°Cand 300°C for 2 hours in vacuum. Different intrinsic and extrinsic structural changes due to heat treatment were determined from FTIR and XRD measurements. When PANI is subjected to heat treatment, different changes are taking place in the system like doping, dedoping (extrinsic), oxidation and changes in crystal structure (intrinsic). Mechanisms for doping, dedoping and oxidation, are proposed.

Abstract: A new type of six-wing synchronous rotor has been designed and manufactured for mixing requirements of the short fiber-rubber composite material. During the manufacturing process of the composite material, different addition proportions of the short fibers have been used. The physical and mechanical performances of the short fiber-rubber composite material have been investigated. The new type rotor meets the mixing requirements of the short fiber-rubber composite material, with the best addition proportion of the short fibers.