Applied Mechanics and Materials Vols. 395-396

Abstract: In order to fabricate a kind of amphiphilic hot-melt pressure sensitive adhesives (HMPSAs) suitable for transdermal drug delivery systems (TDDS) of natural medicines, SIS-based hot-melt pressure sensitive adhesives were modified by a melt-blending method, in which a kind of hydrophilic poly (ethyl acrylate-co-methyl methacrylate-co-trimethylammonioethyl methacrylate chloride) (RLPO) and polyethylene glycol 2000 (PEG2000) were utilized. Functional RLPO and its plasticizer PEG2000 worked as a hydrophilic skeleton of amphiphilic HMPSAs. SEM and FT-IR results indicated that RLPO and SIS were partially compatible with each other through n-π complex between the n electrons of the carbonyl group of RLPO and the π electrons of the benzene rings of SIS and their compound had a good thermal stability. The phase microscope images showed that PEG could improve the compatibility between RLPO phase and SIS phase. As the ratio of SIS/RLPO/PEG equaled to 1/2/1.6, their compounds obtained bi-continuous structures. Geniposide (logP<0) and oleanic acid (logP=9.0) were chosen as representatives of hydrophilic drugs and lipophilic drugs, respectively. It was observed that both hydrophilic drugs and lipophilic drugs had a continuous release in the optimized amphiphilic HMPSAs. In addition, the release behavior of hydrophilic geniposide could be controlled by adjusting the ratio of RLPO to PEG.

Abstract: The nucleation mode of emulsion polymerization of styrene under different emulsifier (SDS) concentrations is studied in this paper. Some factors such as conversion, particle number (Np), fraction of coverage, polydispersion index (PDI) and particle size distribution (PSD) of the reactions were investigated. The results show that when [SD is less than its CMC, homogeneous nucleation dominates. But when [SD is more than its CMC, micelle nucleation plays the major role.

Abstract: The variation trend of polymer particle size under different emulsifier concentrations in emulsion polymerization of styrene were investigated in this paper. The results show that the particle number increases and particle size decreases with the increase of emulsifier concentration. But the particle size growth is controlled by the rate of the monomer migration from water medium to the growing micelles.

Abstract: The curing reaction of the bismaleimide resin system was analyzed by FT-IR spectroscopy and differential scanning calorimetry, and the curing reaction kinetics parameters were characterized. Otherwise the rheological behavior of the bismaleimide resin was studied through tracking the changes of the resin viscosity with reaction temperature and time by using a rotatory viscometer. The rheologic dynamic equation and dynamic index of the resin were also established under the condition of constant temperature.The result showed that the bismaleimide resin system was a typical thermosetting resin. This research will help to optimize the molding process parameters of the bismaleimide resin.

Abstract: Polymerization of high molecular weight PMMA was achieved in [BMIPF₆ by contrasted in cyclohexane, toluene solvent at reaction temperature 60 C, 65C and 70 C, reaction time 60min. The data including the yield, molecular weight and molecular weight distribution of PMMA were analysized in 3 kind of solvent. The results showed that the weight average molecular weight of PMMA in [BMIPF₆ is up to 730000, respectively 7 and 10 times of molecular weight in cyclohexane and toluene. Secondly, the polymerization kinetics of PMMA in [BMIPF₆ were tested, the apparent chain propagation rate constant of PMMA are 10.7×10⁴12.9 ×10⁴ and 19.9×10⁴ in 60 C, 65C and 70 C. Compared with the growth rate constant in toluene, the polymerization rate constant PMMA in the ionic liquid increased by 5~10 times.

Abstract: Composite cellulosic membrane of PMMA and phosphomolybdic acid was prepared by electrospinning. During the progress, the factor of electrospinning and the optimum parameters was found out within the orthogonal combination experiment program. Then the morphology of the composite cellulosic membrane was observed by polarizing microscopy. To resolve PMMA, DMF and anhydrous alcohol were used. When their ratios were 1:1, the diameter of the fibre was the most homogeneous. During the electrospinning, the concentration of PMMA was the most important factor. When the concentrations were less then 10%, there were hardly fibres on the foil. The diameter of the fibre ranged from 0.5 to 1.2 μm along with the increment of the concentration of PMMA. The addition of phosphomolybdic acid made the diameter of the fibre decrease. IR-spectra showed that phosphomolybdic acid kept its Keggin structure, and it interacted with PMMA through hydrogen bond. The composite cellulosic membrane changed its color when imposed in bright space. UV spectra represented that the composite cellulosic membrane had a strong absorption peak at 700nm.

Abstract: Microfibers have huge potential applications in many fields due to their unique properties. However, the high performance thermoplstic microfibers were rarely reported. In this work, Poly (ether sulfone) Microfibers were first successfully prepared by melt extrusion of immiscible blends of PES, Polyamide 6 ( PA6 ), and subsequent removal of PA6 component. The morphologies of the PES microfibers were characterized by SEM. The experimental results showed the PES microfibers exhibited interconnected structures between the fibers and the average diameter was about 150 nm. The present PES microfiber may be applied to the development of ultrafiltration membranes materials.

Abstract: The waterborne polyurethane (WPU) modified by epoxy resin was synthesized by using isophorone diisocyanate (IPDI), poly propylene glycol (PPG-1000), 2,2-dimethylol propionic acid (DMPA) and epoxy resin as the main raw materials. The WPU properties were characterized by TGA, FTIR, and so on. The study shows that when n_NCO/n_OH=1.4, the mount of DMPA is 5.0%, the emulsifying property of WPU which is modified epoxy resin with high epoxy value is well. And when the mounts of E-20, E-44 are 2.0%, 4.0% respectively, the synthesized emulsion with small size has well stability. The modified WPU which possesses high hardness, low water absorption, good heat resistance and anticorrosion, has a well combination property.

Abstract: The article examines the research aimed at studying the basic physico-mechanical parameters of polymer-cement repair mortars with a modified composition. The objective of a composition modification was to achieve the parameters characteristic of fire-resistant repair mortars. For research purposes, a lightweight sintered aggregate-based ash body was used along with polymer fibres based on polyolefin. It was suggested to use a few recipes that have been subjected to high temperature stress up to 1200 °C. Subsequently the suitability of the formula composition was verified by determining the essential characteristics visual assessment of the structure, density, compressive strength and flexural strength. The results point to the suitability of the proposed formulas, although this will be verified by setting other essential material characteristics.

Abstract: In this paper, compared with common fly ash, the low-silicon coal gangue fly ash is used to produce fly ash autoclaved aerated concrete. The influences of water binder ratio, coal gangue fly ash content, calcareous content and conditioning agents on the compressive strength of the autoclaved aerated concrete are investigated. The results indicate the coal gangue fly ash has different properties from the common fly ash such as its granule appearance and the activity as AAC siliceous raw material. It is noting that the coal gangue fly ash can also be used to prepare AAC blocks by optimizing the raw material formulation and procedure and its B05 product can reach the China top industrial standard.