Advanced Materials Research Vol. 1052

Abstract: The effects of styrene-co-maleic anhydride (SMA) compatibilizer on the mechanical thermal and morphological properties of polyoxymethylene (POM)/acrylonitrile-butadiene-styrene (ABS) blends were inverstigated. POM/ABS blends without and with SMA compatibilizer were prepared by an internal mixer and molded by compression molding. It was found that the dispersion of ABS phase and compatibility could not improve by using SMA compatibilizer in POM/ABS blends due to SMA can be miscible with ABS phase more than POM phase. The addition of ABS in a range of 10-30 wt% could improve the Young’s modulus of POM. Impact strength, tensile strength and percent strain at break of POM/ABS blends decreased with increasing ABS content. The addition of compatibilizer improved Young’s modulus of POM/ABS (60/40, 50/50) blends. The addition of ABS increased the degradation temperature of POM, while SMA compatibilizer did not improve the degradation of POM/ABS blends.

Abstract: Sodium polyacrylate as a kind of high absorbent resin, has an excellent water absorption performance, is low in price and isn’t corrosive. Compounds of different particle sizes and components were prepared using sodium polyacrylate and sodium chloride. They were used in the fog chamber to disperse warm fog respectively then. Experiments were carried out to investigate how particle size and composition affect the warm fog dissipation. Results as follows are obtained: the time light transmittance recovers to 60% (t_60%) is 85min when the fog dissipates naturally; 30g sodium polyacrylate whose average size is 30μm has a good effect on warm fog dissipation, t_60% being 14min; when the sodium polyacrylate and sodium chloride are mixed by 1:2 in mass ratio, the fog elimination effect is the best, with t_60% 6min. The reasons are analyzed at the same time.

Abstract: The micro-structure of the surface of Hevea brasiliensis latex particles has been found by the means of atomic force microscopy (AFM), confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), cryogenic transmission electron microscopy (cryo-TEM), and electrokinetics over a broad range of KNO₃ electrolyte concentrations (4-300 mM) and pH values (1-8). Based on the atomic force microscopy analysis of the fresh natural rubber latex, it could be estimated that the protein-lipid layer is covered with the rubber particles. The molecules in the particle were labeled with fluorescent Rhodamine (RB), and were monitored by CLSM. SEM and TEM were used to observe the surface of fresh natural rubber particles and were dyed by osmium tetroxide. Fourier Transform Infrared Spectroscopy (FTIR) has been used to characterize the nitrogenous groups in natural rubber and deproteinized natural rubber (DPNR). The FTIR and ¹H-NMR analysis of phosphatase-treated DPNR confirmed that the presence of mono- and diphosphate terminations without phospholipids was also unlikely owing to the presence of a methylene proton signal of an isoprene unit linked to mono- and diphosphate groups. The , [η] and Higgins’ k’ of DPNR decreased after being treated with lipase.

Abstract: Through the polymerization and grafting reaction of bisphenol A dianhydride and bisphenol A diamine, the polyimide activator (PI activator) of acyl caprolactam end capping is obtained and then the anionic in-situ polymerization modified nylon 6 resin is obtained. Viscosity analysis shows that PI consumption is higher than 0.1 (of monomer mass), the reaction temperature is higher than 160°C, the viscosity rises rapidly in a short time and the rapid polymerization molding can be realized; when PI consumption is higher than 0.15 (of monomer mass), the water absorption of matrix resin will be lower than 1.4%; compared with the nylon resin, its water absorption is significantly lowered and its mechanical property is improved greatly; microscopic analysis shows that PI molecules fail to enter the crystalline phase of the nylon 6 and form lamellar crystals in the nylon matrix, which plays a role of enhancement and obstruction; differential thermal analysis shows that PI reduces the melting enthalpy and melting point temperature of nylon 6 resin, which indicates that PI reduces the crystallization capacity of nylon 6.

Abstract: A study of the effect of the addition of polyethylene glycol grafted cellulose nanocrystals on the properties of a polyurethane matrix was carried out. The resulting nanocomposite films were characterized by scanning electron microscopy, Fourier transform infrared spectrometry, micro–control electronic universal testing machine and thermal gravimetric analysis. Remarkable improvements in the mechanical and thermal properties of polyurethane could be attributed to well–dispersion of nanofillers in polyurethane matrix and the formation of hydrogen bonding network within the polymer matrix.

Abstract: Due to the low strength of ordinary rubber, poor high temperature resistance and abrasion resistance, limit their service life. In this paper, the high-performance carbon fiber (CF) was used as a reinforcement, the chloroprene rubber (CR) as the matrix, and coupling agent as a compatilizer, prepared carbon fiber/rubber composite materials. The content of carbon fiber was determined by testing the mechanical and thermal properties. The effect of coupling agent on the compatibility between rubber and carbon fiber was studied by using as a bonding agent. The compatibility of the carbon fiber and rubber were analyzed by scanning electron microscope (SEM). The results show that the formula obtained best mechanical properties is 100 phr chloroprene rubber, 12 phr carbon fiber, and 2.5 phr KH-550. And further demonstrate that compatibility of carbon fiber / chloroprene rubber with adding 12phr CF by SEM analysis.

Abstract: Fluorine rubber has excellent performance, such as cold resistance, heat resistance, ozone resistance thermal properties and so on. However, fluorine rubber is poor in the mechanical properties. In order to improve its availability of fluorine rubber, short basalt fiber/ fluorine rubber composite materials were prepared by using short basalt fiber as reinforcement, and its mechanical properties and compatibility were studied. The influence of the surface treatment on short basalt fibers, short basalt fiber content on the mechanical properties of short basalt fiber reinforced fluorine rubber composites were studied. The best formulation of short basalt fiber/ fluorine rubber composite materials were determined by testing Shore A hardness, tensile strength and elongation at break. The results show that the formula obtained best mechanical properties is 100 phr fluorine rubber, 10 phr short basalt fiber, and 2.5 phr KH-550. And further demonstrate that compatibility of short basalt fiber / fluorine rubber with KH550 is best by SEM and IR analysis. And prepare excellent performance of fluorine rubber composite materials.

Abstract: In this paper, the self-curable unsaturated polyester was put forward as a new solution to air pollution problems caused by the cross-linking monomer’s volatilization in unsaturated polyesters (UP) industry. Two kinds of unsaturated polyesters with the vinyl double bonds at the side chain were synthesized with Itaconic acid (IA) or Itaconic anhydride (ITA) as raw materials. The first one was prepared with IA, isophthalic acid and propylene glycol (IPP-UP), and the second one was synthesized with glycidol (GL) and ITA (IG-UP). Investigation demonstrates that the latter UP resin could be self-cured through the nucleophilic addition reaction of hydroxyl groups with double bonds or the free-radical homopolymerization of double bonds when they were heated without cross-linking monomers. However, the former couldn’t. Factors on self-crosslinking activity and crosslinking mechamism of pendant vinyl bonds from IA or ITA were explored.¹H-NMR and FT-IR were used to characterize.

Abstract: The effects of potassium citrate (K₃cit) on sedimentation and aggregation of 50 nm calcium oxalate dihydrate (COD) crystals was studied in order to explore the mechanism of formation and inhibition of kidney stone. In four different systems, including pure water, urine of healthy person and CaOx stone former before and after taking medicine K₃cit, the influences of K₃cit on average size (), Zeta potential and optical density of nanoCOD suspensions were studied by nanoparticle size Zeta potential analyzer and ultraviolet spectrophotometer. It was showed that K₃cit could specifically adsorb on nanoCOD crystals, and also competed with the inhibitor molecules in urine. Due to the decrease of inhibitors in urine of patients, K₃cit can be better to fulfill its inhibitory effect, leading to the largest reduced values of the diameter of COD crystal and the optical density of urine suspension. In conclusion, the inhibitory effect of K₃cit on aggregation and sedimentation of calcium oxalate crystals is better in urine of patients, whereas the inhibitory effect has been reduced in urine of control group and patients after taking k₃cit.

Abstract: The aggregation of urine crystallites with different sizes in the urines of 5 cases of uric acid (UA) calculi patients and 5 cases of healthy controls were comparatively investigated by means of nanoparticle size analyzer. Different sizes of urine crystallites were obtained by filtrating the urine through microporous membrane with different pore sizes (0.22, 0.45, 1.2, 3, and 8 μm), respectively. The average particle size () increased rapidly with placement time (t) in the lithogenic patients. The values of the urine crystallites of the controls increased more slowly with t. When t was increased, the autocorrelation curves in the two types of urine crystallites became less smooth and the decay of the correlation curve became slower, and decay time of different sizes of urine crystallites both for the calculi patients and the controls increased. These results indicated that the urine crystallites of the controls were more stable than those of the patients. The rapid aggregation of urine crystallites may be an important factor affecting the growth of crystallites in UA stone patients.