PA6/HDPE/EVA三元共混改性的研究

研究了PA6/HDPE、PA6/HDPE/EVA共混物的密度、热性能和力学性能。PA6/HDPE/EVA三元共混物的力学性能比PA6/HDPE二元共混物有明显提高。对于拉伸强度,EVA的最佳含量在2～4份。冲击强度随EVA含量的增加而提高,EVA的含量小于5份时,对共混物的硬度几乎没有影响。

Melting Behavior of PA6 and PA6/PE Blends Crystallized from Amorphous State

Aim To investigate the melting behavior of polyamide 6 in polyamide 6/polyethy lene blends crystallized from amorphous state. Methods DSC was used to test effects of annealing temperature, annealing time, DSC scan rate, and the step wise annealing on the melting peaks of the ice water quenched specimens. Results and Conclusion Varied melting peaks of PA6 component were obtained. The degree of perfection and the crystallization degree of PA6 crystals decreased in the blends, and the crystallization degree of PA6 increased with the increasing of the annealing time. The height of the upper melting peak of reference PA6 is higher than that in blends.

Effect of Thermal Treatment on the PA-6 in the Blends

Aim To investigate the multiple melting behavior of polyamide 6(PA 6) in polyamide 6/linear low density polyethylene blends crystallized from the crystal amorphous state. Methods\ The effects of annealing temperature, annealing time, heating rate, and the step wise annealing were measured by DSC. Results and Conclusion\ There exists a critical heating rate affecting the middle temperature melting peak. When annealed at the temperature close to the melting peak, the main melting peak of PA 6 shifted to a higher temperature. Within a short time, annealing time has much effect on neat PA 6 but little effect on PA 6 in the blends. Addition of PE results in a decreasing in the height of melting peak. These phenomenon show that the melting behavior of PA 6 was affected by PE, compatibilizer, as well as thermal treatment.

FRACTAL BEHAVIOR OF DEVELOPMENT OF PHASE SEPARATION AND CRYSTALLIZATION IN BLENDS OF NYLON-6 WITH SODIUM SALT OF ETHYLENE /METHACRYLIC ACID COPOLYMER

Phase separation was studied by the optical microscopy in blends of nylon 6 (PA6) with sodium salt of ethylene/methacrylic acid copolymer (PEMA).The image collecting technology was used to keep track of the development of blends at a certain temperature.The fractal dimension of phase separation was calculated by the image solving technology according to the fractal theory and the self similarity behavior of the process was proved.The relationship of the fractal behavior with composition and experimental temperature was discussed.The fractal behavior of the crystallization development of the crystal phase of PA6 in blends was also discussed and the fractal behavior calculated.

Non-isothermal crystallization kinetics of Nylon 10T and Nylon 10T/1010 copolymers:Effect of sebacic acid as a third comonomer

Nylon 10 T and Nylon 10T/1010 samples were synthesized by direct melt polymerization. The non-isothermal crystallization kinetics of Nylon 10 T and Nylon 10T/1010 was investigated by means of differential scanning calorimetry(DSC). Jeziorny equation and Mo equation were applied to describe the non-isothermal crystallization kinetics of the Nylon 10 T and the Nylon 10T/1010. The activation energies for non-isothermal crystallization were obtained by Vyazovkin's method and Friedman's method, respectively. These results showed that Jeziorny equation and Mo equation well described the non-isothermal crystallization kinetics of the Nylon 10 T and the Nylon 10T/1010. It was found that the values of the activation energy for non-isothermal crystallization of the Nylon 10T/1010 were lower than those of the Nylon 10 T at a given temperature or relative crystallinity degree,which revealed that crystallization ability of the Nylon 10T/1010 was higher. The crystal morphology was observed by means of a polarized optical microscope(POM) and X-ray diffraction(XRD). It was found that the addition of sebacic acid comonomer not only did not change the crystal form of the Nylon 10 T, but also significantly increased the number and decreased the size of spherulites. Comparing with the Nylon 10 T, the crystallization rate was increased with the addition of the sebacic acid comonomer.

Research progress of high temperature resistant nylon 10T

Researches about synthesis and modification of nylon 10T(PA10T)in domestic universities and scientific research institutions are reviewed in this paper.The results show that,due to the different performance requirements,PA10T is studied from the co-polymerization,blending modification and filling modification of these three aspects.Meanwhile,the existing problems are analyzed and the development prospect of PA10T is predicted.

Isothermal and nonisothermal crystallization kinetics of bio-sourced nylon 69

Bio-sourced nylon 69,one of promising engineering plastics,has a great potential in developing sustainable technology and various commercial applications.Isothermal and nonisothermal crystallization kinetics of nylon 69 is a base to optimize the process conditions and establish the structure–property correlations for nylon 69,and it is also highly bene ficial for successful applications of nylon products in industry.Isothermal and nonisothermal crystallization kinetics has been investigated by differential scanning calorimetry for nylon 69,bio-sourced even–odd nylon.The isothermal crystallization kinetics has been analyzed by the Avrami equation,the calculated Avrami exponent at various crystallization temperatures falls into the range of 2.28 and 2.86.In addition,the Avrami equation modi fied by Jeziorny and the equation suggested by Mo have been adopted to study the nonisothermal crystallization.The activation energies for isothermal and nonisothermal crystallization have also been determined.The study demonstrates that the crystallization model of nylon 69 might be a twodimensional(circular)growth at both isothermal and nonisothermal crystallization conditions.Furthermore,the value of the crystallization rate parameter(K)decreases signi ficantly but the crystallization half-time(t1/2)increases with the increase of the isothermal crystallization temperature.To nonisothermal crystallization,the crystallization rate increases as the cooling rate increases according to the analysis of Jeziorny's theory.The results of Mo's theory suggest that a faster cooling rate is required to reach a higher relative degree of crystallinity in a unit of time,and crystallization rate decreases when the relative degree of crystallinity increases at nonisothermal crystallization conditions.

Comparison of wear behavior of ABS and Nylon6-Fe powder composite parts prepared with fused deposition modelling

Fused deposition modeling(FDM) is one of the latest rapid prototyping techniques in which parts can be manufactured at a fast pace and are manufactured with a high accuracy. This research work is carried out to study the friction and wear behavior of parts made of newly developed Nylon6-Fe composite material by FDM. This work also involves the comparison of the friction and wear characteristics of the Nylon6-Fe composite with the existing acrylonitrile butadiene styrene(ABS) filament of the FDM machine. This Is carried out on the pin on disk setup by varying the load(5, 10, 15 and 20 N) and speed(200 and 300 r/min). It is concluded that the newly developed composite is highly wear resistant and can be used in industrial applications where wear resistance is of paramount importance. Morphology of the surface in contact with the Nylon6-Fe composite and ABS is also carried out.

Protective effect of prednisolone on ischemia-induced liver injury in rats

AIM: To investigate the effects of prednisolone on cell membrane bleb formation, calpain μ activation and talin degradation during hepatic ischemia-reperfusion injury in rats. METHODS: The hilar area of the left lateral and median lobes of rat liver (68%) was clamped for 60 min and followed by 120 min reperfusion. Prednisolone was administered at 1.0, 3.0, or 10 mg/kg at 30 min before ischemia. In addition to biochemical and microscopic analyses, activation of calpain μ was determined using specific antibodies against the intermediate (activated) form of calpain μ. Degradation of talin was also studied by Western blotting. RESULTS: In the control and prednisolone (1.0 mg/kg) groups, serum aspartate transaminase (AST) and alanine transaminase (ALT) level were elevated, and cell membrane bleb formation was observed after 120 min of reperfusion. Moreover, calpain μ activation and talin degradation were detected. Infusion of prednisolone at 3.0 or 10 mg/kg significantly suppressed serum AST and ALT, and prevented cell membrane bleb formation. At 10 mg/kg, prednisolone markedly suppressed calpain μ activation and talin degradation. CONCLUSION: Prednisolone can suppress ischemia- reperfusion injury of the rat liver. Its cytoprotective effect is closely associated with the suppression of calpain μ activation and talin degradation.

Thermotics Study of the Semimetallic Nylon1010 Composite

Thermal expansion characteristics of semimetal nylon composites (nylon 1010 incorporated with metal oxides) were analyzed with thermal expansion instrument. The changes of composite weight after being heated and the heat absorption and release of the composites were analyzed by carrying out TG-DSC experiments. Experimental results show that the average thermal expansion coefficient of the composites rises as the average diameter of the metal oxides decrease from room temperature to 160 ℃. Thermal dynamics and physical properties of the nylon composites change with the addition of the oxides; the crystallization temperature rises from 180 ℃ of pure nylon to 190 ℃ (maximum) and the melting point of the oxide composites also increases continuously with the addition of the oxides. The water content of the oxide/nylon composite is related to the kind and content of the oxide. The water content reaches its maximum when the content of oxide is 10%, and the 10% Al2O3/nylon composite has a water absorption ratio up to 1%.

Statistical Constitutive Equation of Aramid Fiber Bundles

Tensile impact tests of aramid (Twaron) fiber bundles were carried out under high strain rates with a wide range of 0. 01/s -1 000/s by using MTS and bar-bar tensile impact apparatus. Based on the statistical constitutive model of fiber bundles, statistical constitutive equations of aramid fiber bundles are derived from statistical analysis of test data at different strain rates. Comparison between the theoretical predictions and experimental data indicates statistical constitutive equations fit well with the experimental data, and statistical constitutive equations of fiber bundles at different strain rates are valid.

Bending and Washing Reliabilities of Screen-Printed UHF RFID Tags Based on Woven Water-Mark Fabric

Compared with bar code and quick response( QR) code in the storage and retailing management of textiles, the ultra-high frequency( UHF) radio frequency identification( RFID) tags have high information capacity as well as reliability in complex environmental conditions. In this study,the UHF RFID tags with perfect integration with textiles are assembled with screen-printed antenna on woven water-mark nylon fabric and Alien UHF integrated circuit( IC), and their reading performance under various washing and bending conditions is evaluated by an RFID reader. The results show that the tags after fifty bending( both arch and sink) cycles of screen-printed antenna still have reading distance more than 5.5 m,and an average reading distance is over 4.0 m after five washing cycles. The experimental results demonstrate that the tag antenna on the water-mark fabric can be manufactured by the screen-printing technology,and a coating process on this fabric facilitates the reading performance and the resistance against complex mechanical impact.

Treatment of radiation-induced hemorrhagic gastritis with prednisolone:A case report

Radiation-induced gastritis is an infrequent cause of gastrointestinal bleeding.It is a serious complication arising from radiation therapy,and the standard treatment method has not been established.The initial injury is characteristically acute inflammation of gastric mucosa.We presented a 46-year-old male patient with hemorrhagic gastritis induced by external radiotherapy for metastatic retroperitoneal lymph node of hepatocellular carcinoma.The endoscopic examination showed diffuse edematous hyperemicmucosa with telangiectasias in the whole muscosa of the stomach and duodenal bulb.Multiple hemorrhagic patches with active oozing were found over the antrum.Anti-secretary therapy was initiated for hemostasis,but melena still occurred off and on.Finally,he was successfully treated by prednisolone therapy.We therefore strongly argue in favor of perdnisolone therapy to effectively treat patients with radiation-induced hemorrhagic gastritis.

Newly developed autoimmune cholangitis without relapse of autoimmune pancreatitis after discontinuing prednisolone

A 57-year-old man presented with a 2-wk history of painless jaundice and weight Iossl He had a large ill- defined enhancing mass-like lesion in the uncinate pro- cess of the pancreas with stricture of the distal common bile duct. Aspiration cytology of the pancreatic mass demonstrated inflammatory cells without evidence of malignancy. Total serum immunoglobulin G level was slightly elevated, but IgG4 level was normal. After the 2-wk 40 mg prednisolone trial, the patient＇s symptoms and bilirubin level improved significantly. A follow-up computed tomography （CT） scan showed a dramatic resolution of the pancreatic lesion. A low dose steroid was continued. After six months he self-discontinued prednisolone for 3 wk, and was presented with jaundice again. ACT scan showed newly developed intrahepatic biliary dilatation and marked concentric wall thickening of the common hepatic duct and the proximal common bile duct without pancreatic aggravation. The patient＇ s IgG4 level was elevated to 2.51 g/L. Prednisolone was started again, after which his serum bilirubin level became normal and the thickening of the bile duct was resolved. This case suggests that autoimmune pancre- atitis can progress to other organs that are not involved at the initial diagnosis, even with sustained pancreatic remission.

Non-isothermal crystallization kinetics of reactive microgel/nylon 6 blends

The non-isothermal crystallization kinetics of reactive microgel/nylon 6 blends was investigated by differential scanning calorimetry(DSC). The Mo equation was employed to analyze the non-isothermal crystallization data. The crystallization activation energies were also evaluated by the Kissinger method. The results show that the crystallization onset temperature(T onset) and crystallization peak temperature(T p) decrease with the increase of the content of reactive microgel, while ΔT(T onset–T p), the crystallization half-time(t1/2) and the crystallization enthalpy(ΔH c) increase. The required cooling rates of blends are higher than that of neat nylon6 in order to achieve the same relative crystallinity in a unit of time. The crystallization activation energies of the reactive microgel/nylon 6 blends are greater than those of the neat nylon 6. When the content of reactive microgel is 30%, the relative crystallinity(X t) reaches the maximum.

Separation of Oil Phase from Dilute Oil/Water Emulsion in Confined Space Apparatus

A miniature process for separating the oil phase from dilute oil/water emulsion is developed.This process applies a confined space apparatus,which is a thin flow channel made of two parallel plastic plates.The space between the two plates is rather narrow to improve the collisions between oil droplets and the plate surface.Oil droplets have an affinity for the plate surface and thus are captured,and then coalesce onto the surface.The droplet size distribution of the residual emulsion resulted from the separation process is remarkably changed.The oil layer on the plate weakens the further separation of oil droplets from the emulsion.Three types of plate materials,polypropylene(PP),polytetrafluoroethylene(PTFE) and nylon 66,were used.It is found that PP is the best in terms of the oil separation efficiency and nylon 66 is the poorest.The interaction between droplets in the emulsion and plate surface is indicated by the spreading coefficient of oil droplet on the plate in aqueous environment,and the influences of formed oil layer and plate material on the separation efficiency are discussed.

Experimental and simulation study of nylon 6 solid–liquid extraction process

The solid–liquid extraction process of nylon 6 to eliminate small molecules, i.e., caprolactam(CL), cyclic dimers(CD) and cyclic trimers(CT), is investigated in detail by both batch extraction experiments and numerical simulations. In the batch extraction experiments, due to the small molecules attaching to the polymeric surface, the basic physical mechanism shifts from surface diffusion to internal diffusion as the extraction proceeded. The experimental data are well reproduced by a diffusion model consisting of two distinct steps, characterized as surface diffusion and internal diffusion. Furthermore, based on the established mass transfer mechanism and diffusion model of the two distinct steps, the equilibrium constants and internal diffusion coefficients of CL, CD and CT are acquired. An industrial countercurrent extraction tower is further simulated. It is found that the extraction efficiency of CL can be significantly improved by increasing the temperature at the bottom portion of the tower. The elimination of CD, which can be greatly promoted by a high-concentration CL-water solution, is controlled by mass transfer resistance, whereas the removal of CL is mainly affected by the equilibrium.

Influences of Reactive Compatibilizer R-Styrene-Maleic Anhydride Copolymer on PA6/PP Blends

The effect of R-styrene-maleic anhydride copolymer （R- SMA） compatibilzation on Nylon 6 （ PA6 ）/polypropylene （ PP ） blends has been investigated experimentally through Molan test, microscopic morphology, and chemical structure. Results show that the moderate R-SMA addition can promote reaction between anhydride in R-SMA and amino in PA6, and lead to a new PA6-g- R-SMA copolymer in the blends. Such PA6-g-R-SMA eopolymer in the blends can effectively reduce the interfaeial tension and PP particle size, and improve the compatibility of two immiscible phases in the blends. The crystallinity of PA6 in PA6/PP blends has greatly decreased by PP blends. The blends have the best comprehensive mechanical and thermal properties when the mass ratio of PA6/PP/ R-SMA is 90：10：2 to 90：10：4. The impact strength of the PA6/PP blends with the eompatibilizer is increased by more than 150 %.

A Combined System for Biological Removal of Nitrogen and Carbon from Nylon-6 Production Wastewater

A combined system consisting of hydrolysis acidification, denitrification and nitrification reactors was used to remove carbon and nitrogen from the nylon - 6 production wastewater, which was characterized by good biodegradability and high nitrogen concentration. The influences of Chemical Oxygen Demand （COD） in the influent, recirculation ratio, Hydraulic Residence Time （HRT） and Dissolved Oxygen （DO） concentration on the system performances were investigated. From results it could be seen that good performances have been achieved during the overall experiments periods, and COD, Total Nitrogen （TN）, NH^＋ -N and Suspended Solids （SS） in the effluent were 53, 16, 2 and 24 mg· L^-1, respectively, which has satisfied the first standard of wastewater discharge established by Environmental Protection Agency （EPA） of China. Furthermore, results showed that operation factors, viz. COD in the influent, recirculation ratio, HRT and DO concentration, all had important influences on the system performances.

Measurement of large deformation of nylon cord-rubber composite and effects of perpendicular loads on its stress-strain behaviors

Effects of transverse loads on longitudinal stress strain behaviors and longitudinal constant tensile loads on transverse stress strain behaviors of single ply of nylon cord rubber composite are studied respectively under biaxial tensile condition with cruciform specimen. Effects of transverse constant tensile load on longitudinal tensile mechanical properties are indistinctive compared with corresponding uniaxial longitudinal tensile mechanical properties. It can be relative to larger difference between longitudinal and transverse mechanical properties. Its dominating failure mode is typical fiber dominated mode; However, Experiment results indicate that transverse mechanical properties of nylon cord rubber composite with longitudinal constant tensile loads are distinct from its uniaxial transverse tensile mechanical properties. It can be attribute to action of longitudinal tension that makes material rigidify in the direction perpendicular to fiber, Mode of failure is representative of matrix dominated failure. For the measurement of large deformation up to 50 percent, a special CCD imaging method is employed in the experimental investigation that makes measurement of large deformations more precise.