AS／EVA／NBR共混体系研究

本文研究了ＡＳ／ＥＶＡ／ＮＢＲ共混体系性能与组成比，形态结构的关系；并研究了ＮＢＲ组成对共混体系性能的影响。结果表明ＥＶＡ可作为ＡＳ与ＮＢＲ的相容剂；适量ＥＶＡ可以大幅度提高共混物的冲击韧性，且可改善制品外观；共混物具有优良的常，低温冲击韧性。较好的其它力学性能性。ＴＥＭ观察结果揭示ＥＶＡ的加入可使ＮＢＲ颗粒分布均匀，粒径变小；部分ＥＶＡ处于ＮＢＲ颗粒与ＡＳ基本相界面上，起着相容的作用。     

Dual lamellar crystal structure in poly(vinylidene fluoride)/acrylic rubber blends and its biaxial orientation behavior

The miscibility for melt-mixed poly(vinylidene fluoride) (PVDF)/acrylic rubber (ACM) blends and the crystal morphology of PVDF in the blends were investigated over the whole composition ranges by dynamic mechanical analysis (DMA), wide-angle X-ray diffraction (WAXD), small-angle X-ray scattering (SAXS), and transmission electron microscopy (TEM). DMA measurements revealed that PVDF is miscible with ACM in ACM-rich system, and partially miscible in PVDF-rich system. Two kinds of PVDF lamellar structures with different long periods were detected by SAXS and TEM for the partially miscible blends. In the miscible system, only one kind of crystal lamellae with enlarged long period is found. The two kinds of lamellar structures in the blend show different orientation behavior during the uniaxial stretching to result in a biaxial orientation. The lamellae with short long period are oriented vertical to the stretching direction, while those with large long period were found to be oriented parallel to the stretching direction.     

Study on antibacterial O-carboxymethylated chitosan/cellulose blend film from LiCl/N, N-dimethylacetamide solution

Two types of O-carboxymethylated chitosan (O-CMCh)/cellulose polyblends were prepared by mixing cellulose LiCl/N,N-dimethylacetamide (DMAc) solution with O-CMCh aqueous solution (I) or DMAc emulsion (II) and their corresponding films (I and II) were regenerated in water. The (O-CMCh)/cellulose films obtained were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and wide-angle X-ray-scattering (WAXS). FTIR analyses showed that amino groups of O-CMCh were not affected during the film formation. SEM observations indicated that the O-CMCh/cellulose polyblend displayed a heterogeneous microstructure. O-CMCh microdomains dispersed in the cellulose matrix of the blend film. Blend film I showed a better dispersion of the O-CMCh microdomains than blend film II did. DSC and WAXS analyses suggested that, for both two kinds of the blend films, the addition of O-CMCh did not significantly influence the crystallinity and thermal properties of cellulose. The antibacterial activity of the films against Escherichia coli (E. coli) was also measured via optical density method. Both blend films I and II exhibited satisfying antibacterial activity against E. coli, even the O-CMCh concentration was only 2 wt%. Due to the coagulation effect of water on the polyblend, O-CMCh water solution is suitable for the preparation of the blend film with low O-CMCh concentration, while O-CMCh DMAc emulsion should be selected when high O-CMCh concentration is needed.     

动态硫化了腈橡胶／酚醛树脂共混型热塑性弹性体性能的研究

用动态硫化法制备了丁腈（ＮＢＲ）／酚醛树脂（ＰＦ）共混型热塑性弹性体。研究了ＮＢＲ中丙烯腈含量、ＰＦ品种、橡塑并用比和硫化体系对共混物性能的影响。研究结果表明：随ＮＢＲ中丙烯腈含量的增加，共混物的强度有所提高；随ＰＦ用量的增加，共混物的拉伸强度显著提高，耐油性能和老化性能均得到明显提高：硫磺硫化体系可使ＮＢＲ／ＰＦ并用体系硫化胶有较好的物理机械性能。     

利用规整接枝共聚物作为增容剂制备耐油热塑性弹性体

通过大单体技术合成了三种现整接校共聚物；主链为聚甲基丙烯酸及支链为甲基丙烯酸甲酯的接枝共聚物（ＰＭＡＡ－ｇ－ＰＭＭＡ）可用作氨醇橡胶与聚氯乙烯的熔融共混的增容剂，而主链为聚丙烯酰胺、支链为聚苯乙烯的接校共聚物（ＰＡＭ—ｇ－ＰＳ）及主链为聚甲基丙烯酸甲酯、支链为聚苯乙烯的接枝共聚物都能作为氯化聚乙烯与聚苯乙烯共混的增容剂。用量仅占２％即可制得耐油的热塑性共混物弹性体。     

Compatibilizing effects of block copolymer mixed with immiscible polymer blends by solid-state shear pulverization: stabilizing the dispersed phase to static coarsening

A continuous, industrially scalable process called solid-state shear pulverization (SSSP) leads to compatibilization of polystyrene (PS)/high-density polyethylene (HDPE) blends by addition of a commercially available styrene/ethylene-butylene/styrene (SEBS) triblock copolymer. Partial or full compatibilization is characterized by a reduction or elimination of coarsening of the dispersed-phase domains during high-temperature (190 °C), static annealing. In the case of a 90/10 wt% PS/HDPE blend, processing with 3.5 wt% SEBS block copolymer by SSSP yields a coarsening rate that is reduced by a factor of 10 (six) relative to a melt-mixed blend without copolymer (with 3.5 wt% SEBS block copolymer). Addition of 5.0 wt% SEBS block copolymer to the 90/10 wt% PS/HDPE blend during SSSP yields a reduction in coarsening rate by a factor of thirty relative to a melt-mixed blend without copolymer. With an 80/20 wt% PS/HDPE blend, pulverization with 10 wt% SEBS block copolymer yields cessation of coarsening when the average dispersed-phase domain diameter reaches 1.6-1.7 μm. The implications of these results for developing a new, technologically attractive method for achieving compatibilization of immiscible polymer blends are discussed.     

橡胶改性PP各组分与界面区域的协同效应

橡胶增韧ＰＰ为多相结构体系，橡胶粒径、粒子微区结构和界面层结构是影响共混物增韧效果的主要因素；界面层结构是ＰＰ非晶部分和橡胶链段的相互扩散和缠结粘合的结果；通过对共混界面的增容和交联增容．加强界面相容稳定性和粘结力，充分发挥橡胶微区结构和界面层结构在共混物中的韧性作用。     

如何建设和谐校园文化

良好的校园文化是学校持续发展的“助推器999是维护稳定的“稳定剂”,更是改革发展的“催化剂”。推进校园文化建设,既是一个把教育事业融入文化的过程,又是一个以文化促进教育事业发展的过程。因此,无论是同学之间、师生之间的团结和谐,还是学校与教员的协调发展,都离不开校园文化的支撑。     

Experimental study on the auto-ignition and combustion characteristics in the homogeneous charge compression ignition (HCCI) combustion operation with ethanol/n-heptane blend fuels by port injection

This article investigates the auto-ignition, combustion, and emission characteristics of homogeneous charge compression ignition (HCCI) combustion engines fuelled with n-heptane and ethanol/n-heptane blend fuels. The experiments were conducted on a single-cylinder HCCI engine using neat n-heptane, and 10%, 20%, 30%, 40%, and 50% ethanol/n-heptane blend fuels (by volume) at a fixed engine speed of 1800 r/min. The results show that, with the introduction of ethanol in n-heptane, the maximum indicated mean effective pressure (IMEP) can be expanded from 3.38 bar of neat n-heptane to 5.1 bar, the indicated thermal efficiency can also be increased up to 50% at large engine loads, but the thermal efficiency deteriorated at light engine load. Due to the much higher octane number of ethanol, the cool-flame reaction delays, the initial temperature corresponding the cool-flame reaction increases, and the peak value of the low-temperature heat release decreases with the increase of ethanol addition in the blend fuels. Furthermore, the low-temperature heat release is indiscernible when the ethanol volume increases up to 50%. In the case of the neat n-heptane and 10% ethanol/n-heptane blends, the combustion duration is very short due to the early ignition timing. For 20–50% ethanol/n-heptane blend fuels, the ignition timing is gradually delayed to the top dead center (TDC) by the ethanol addition. As a result, the combustion duration prolongs obviously at the same engine load when compared to the neat n-heptane fuel. At overall stable operation ranges, the HC emissions for n-heptane and 10–30% ethanol/n-heptane blends are very low, while HC emissions increase substantially for 40% and 50% ethanol/n-heptane blends. CO emissions show another tendency compared to HC emissions. At the engine load of 1.5–2.5 bar, CO emissions are very high for all fuels. Beside this range, CO emissions decrease both for large load and light load. In terms of operation stability of HCCI combustion, for a constant energy input, n-heptane shows an excellent repeatability and light cycle-to-cycle variation, while the cycle-to-cycle variation of the maximum combustion pressure and its corresponding crank angle, and ignition timing deteriorated with the increase of ethanol addition.     

EVA接枝马来酸酐增韧聚酰胺66

研究了EVA接枝马来酸酐(EVA-g-MAH)用量对聚酰胺66(PA66)性能的影响。结果表明:EVA-g-MAH分散相颗粒对PA具有显著的增韧改性作用。