Advanced Materials Research Vols. 602-604

Abstract: In this paper, bagasse cellulose was dissolved in ionic liquid (1-butyl-3-methylimidazolium chloride) by microwave heating. The orthogonal test and variance analysis were applied to obtain the optimum dissolution condition of bagasse in ionic liquid. The effects of microwave power, temperature and the mass fraction of cellulose were examined by an orthogonal experiment designed through the different dissolution time and the yield of regeneration bagasse. Results showed that the optimal dissolution condition for faster dissolution time was 1% of bagasse cellulose in ionic liquid at 140°C, 500W; while, to get the most yield of cellulose, the condition was 2% of bagasse cellulose at 130°C, 500W.

Abstract: A new accelerated characterization model for creep performances was briefly introduced first, which considers both the effects of temperature and stress level, named time-temperature- stress superposition principle (TTSSP). TTSSP assumes that the influence of stress level on the intrinsic time is similar to that of temperature for the creep behavior, as well as damage and physical aging. The creep curves at different state can be shifted into a master curve at reference state using TTSSP. Then the long-term creep behavior of viscoelastic materials at lower temperature and/or stress level can be predicted from the short-term ones. Finally, TTSSP was used to investigate the nonlinear creep behavior of high-density polyethylene (HDPE). It was shown that the long-term creep behavior of HDPE can be predicted successfully.

Abstract: The melt blending was used to prepare the PP/LLDPE blend, and the layered structure and properties for PP/LLDPE blends were detailed explored. The addition of LLDPE was beneficial to toughen the PP injection moldings. The impact strength also improved for addtion of LLDPE and the corresponding increase percentage in impact strength was 111% for PP/LLDEPE (65/35, w/w) comapred with pure PP. SEM showed the preferred orientation of lamella obtained in shear layer and core region. WAXD curves showed the peak of (300) β-form for PP component in the skin and core region was evident and nearly disappeared in the shear layer, and the (200) peak for LLDPE component in the skin was stronger than that in the shear layer and core region. The enthalpy value calculated by DSC data increased from the core region to the skin, which indicated the crystallinity for PP/LLDPE blends increased from the core region to the skin.

Abstract: Thermoplastic vulcanizates (TPVs) based on epoxidized natural rubber (ENR) and polypropylene (PP) were prepared in an internal mixer at 180°C. The effects of curing systems (i.e., sulfur and peroxide) on morphological, rheological, thermal and mechanical properties were studied. It is found that the sulfur cured TPVs show higher tensile strength, tear strength and elongation at break than those cured with the DCP systems. The rheological analysis indicates that TPVs cured with DCP system show lower apparent shear viscosity than those with sulfur system. SEM studies show that TPVs vulcanized with DCP system exhibit smaller and finely dispersed rubber domains, which provides it higher thermal stability than sulfur cured TPVs.

Abstract: Heterocyclic oligomer based on BBT bearing solubilizing side chains have been synthesized in high yields over six steps from readily available starting materials. This approach offers a much milder, shorter, and more efficient route to BBT derivatives than current methods. This unit can then be used in the synthesis of low bandgap materials via palladium-catalyzed coupling reactions.

Abstract: Network of epoxidized natural rubber that have different epoxidation degree(ED) were measured by 1H-NMR relaxation. Different epoxidation degree ENR showed different molecular mobility due to variations in crosslink density. The temperature dependence of T1, T2 has also been measured.

Abstract: For the purpose of recycling of cotton waste cuttings and exploring the prospect of preparation for super absorbent polymer (SAP), the high viscosity carboxymethyl cellulose (CMC) was made from cotton waste first and then the SAP was synthesized by grafting acrylic acid (AA) onto the CMC with the potassium persulfate being as initiator, N, N'-methylene bis acrylamide as crosslinker. The impact of polymerization temperature, time, initiator dosage, AA concentration, crosslinker dosage, and neutralization degree on water absorbency of SAP was studied. The optimum conditions are mass ratio of AA and CMC 7.11 g/g, initiator dosage 0.03 g/g CMC, crosslinker dosage 0.2 g/100g AA, neutralization degree 80% and polymerization time 1.5 h at 70°C of the polymerization temperature. The water retention of the polymer is good and the water absorbency reaches up to 702.5 g/g.

Abstract: Polylactic acid (PLA)/bagasse fiber (BF) composites were prepared via melt blending. The melting and crystallization behavior, morphology and mechanical properties of the composites were studied by means of differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and mechanical tests. The results indicate that the crystallization ability of PLA is improved with the addition of BF. Silane treatment improves the adhesion between BF and the matrix. Compared with pure PLA, the flexural modulus increases, while the notched impact strength decreases for BF/PLA composites.

Abstract: The terpolymer was synthesized by AM, AA and AMPS. The effects of the content of AA and AMPS, the amount of initiator, the neutralization degree, reaction temperature, reaction time and monomer concentration on terpolymer viscosities were studied. Then it draws the best conditions of this polymerization: monomer quality ratio(AM:AMPS: AA) is 10:2:1, the amount of initiator is between 0.20% and 0.25%, the neutralization degree is 90%, the reaction temperature is 30°C , the reaction time is 4 hours, the total monomer concentration is 21%. Finally, it draws a conclusion that the polymer is a kind of terpolymer which is synthesized by AM, AA and AMPS with the help of the IR spectroscopy.

Abstract: A special optical approach for the study of polymer melts in a slit die is presented in this article. A light scattering imaging system, which is the most suitable for digital evaluation of flow field of polymer melts, is put forward. Bright image of polymer melts against in dark slit die which is suitable for binary processing can be obtained by the CCD. Optical image real-time processing software for recording light intensity matrix at different screw rotate speed and for computing maximum intensity projection area has been developed. And the relationship between maximum intensity projection area and vibration frequency can be predicted by the software. The technique allows the visualization of the light scattered by optical image real-time analysis software to characterize polymer processing. The software brought the qualitative analysis of the flow field of polymer melts success.