Toxicity and Biodegradability Behavior of Xenobiotic Chemicals Before and After Ozonation: A Case Study with Commercial Textile Tannins

Ozonation of a natural tannin (NT; COD_o?=?1195 mg/L; TOC_o?=?342 mg/L; BOD_5,o?=?86 mg/L) and a synthetic tannin ST; COD_o?=?465 mg/L; TOC_o?=?55 mg/L; BOD_5,o?=?6 mg/L) being frequently applied in the polyamide dyeing process was investigated. Synthetic wastewater samples containing these tannins individually were prepared and subjected to ozonation at varying ozone doses (625– 1250 mgO₃/L wastewater), at pH?=?3.5 (the application pH of tannins) and pH?=?7.0 at an ozone dose of 1125 mgO₃/L wastewater. The collective environmental parameters COD, TOC, BOD₅, UV₂₅₄ and UV₂₈₀ (UV absorbance at 254 nm and 280 nm, representing aromatic and unsaturated moieties, respectively) were followed during ozonation. Changes in the biodegradability of the tannins were evaluated in terms of BOD₅ measurements conducted before and after ozonation. In addition, activated sludge inhibition tests employing heterotrophic biomass were run to elucidate the inhibitory effect of raw and ozonated textile tannins towards activated sludge biomass. Partial oxidation (45% COD removal at an ozone dose of 750 mg O₃/L wastewater and pH?=?3.5) of ST was sufficient to achieve elimination of its inhibitory effect towards heterotrophic biomass and acceptable biodegradability improvement, whereas the inhibitory effect and biodegradability of NT could not be reduced via ozonation under the same reaction conditions.     

Multiple thermosetting of semicrystalline polymers: Polyamide 66 and poly(ethylene terephthalate) fibers

Polyamide 66 fibers were thermoset in a torsion-bending deformation at various temperatures up to 240 °C. Some of the fibers were heat-set at constant length prior to the deformation at presetting temperatures of 150 °C and 200 °C to vary the structural state of the starting material. Fractional recovery was measured after various combinations of temperature and time. It was found that heat setting of PA66 is dominated by time-dependent stress relaxation exhibiting time-temperature equivalence. Increased crystallinity, and/or other molecular rearrangements occurring during presetting, impose additional constraints on molecular mobility, which delay onset of the flow regime and increase the time constant of relaxation at a given temperature. The thermosetting characteristics of PA66 fibers are very similar to those of poly(ethylene terephthalate) fibers. For both polymers, superposing the curves of fractional recovery vs. setting time at different temperatures produce satisfactory master curves, without the need for vertical shifting of the data. Arrhenius plots yield approximate activation energies for the thermosetting flow process of 35-65 kcal/mol in PA66 and 95-115 kcal/mol in PET.     

Synthesis and characterization of adamantane-containing poly(enaminonitriles)

The first aliphatic bis(chlorovinylidene cyanide) monomer, 1,3-bis(1-chloro-2,2-dicyanovinyl)adamantane, has been synthesized and polymerized with appropriate diamines to give adamantane-containing aromatic-aliphatic and all aliphatic poly(enaminonitriles) (PEANs) via vinylic nucleophilic substitution polymerization. The PEANs showed excellent solubility in polar aprotic solvents and good thermal stability (10% weight loss in air > 320 °C), despite the aliphatic contents of the polymers. Solution inherent viscosities of 0.23-0.90 dL/g were obtained.Three other new PEANs containing the adamantane-based cardo group were also synthesized via vinylic nucleophilic substitution polymerization from the adamanaine-containing cardo diamine 2,2-bis[4-(4-aminophenoxy)phenyl]adamantane. The cardo PEANs showed better solubility in common organic solvents than the corresponding cardo polyamides. They also showed good thermal stabilities (10% weight loss in air > 339 °C) comparable to those of the corresponding cardo polyamides.     

Properties of polyamide 6/clay nanocomposites processed by low cost bentonite and different organic modifiers

Nanocomposites based on polyamide 6 have been directly prepared by melt compounding, using modified low cost bentonites by three selected quaternary ammonium cations, in particular quaternized octadecylamine (ODA), dimethyl benzyl hydrogenated tallow quaternary ammonium (B2MTH) and dimethyl hydrogenated ditallow quaternary ammonium (2M2TH). Thermal stability of organic modifiers and organoclays has been studied by TGA and results allow evaluating the degree of modifier incorporation into clay galleries. The influence of the organic modifier on the morphology and properties of the obtained nanocomposites has been studied by X-ray diffraction and TEM analysis. Depending on the degree of bentonite modification, different mechanisms were reported to explain the improved mechanical properties of the resulting nanocomposites.     

PPO/PA合金的研制

比较了三条技术路线、PPO／PA质量比、各种抗冲击剂对PPO／PA合金性能的影响。应用FTIR．Molau实验、DSC曲线证实了改性反应原理及增容作用。结果表明：在双螺杆挤出机中,聚苯醚(PPO)与马来酸酐(MAH)接枝反应,然后与聚酰胺(PA66)、SEBS挤出共混,制成的PPO／PA合金,抗冲击性能高。     

POE和POE-g-MA对PA66复合材料结构和性能的影响

分别研究了乙烯一辛烯共聚物（POE）和马来酸酐接枝乙烯-辛烯共聚物（POE-g-MA）对尼龙66（PA66）和20wt％纳米碳酸钙／尼龙66（nano-CaCOJPA66）复合材料力学性能和熔体流动速率（MFR）的影响,用扫描电子显微镜（SEM）、差示扫描式量热法（DSC）和X射线衍射（XRD）等观察和表征了复合材料的形貌和结构。研究表明,POE或POE-g-MA可改善PA66熔体的加工性能,提高PA66的结晶温度。与非相容性POE／PA66和20wt％纳米CaCOJPOE／PA66共混体系相比较,POE-g-MA能明显地细微分散在PA66和20wt％CaCOJPA66复合材料中,促进界面结合,通过有效应力传递赋予复合材料较高的冲击韧性．使拉伸强度的降低程度减弱。     

特达~在户外运动服中的运用

特达 ○R纤维是尼龙 6 6的改良产品 ,是通过异形、复合、混纤、变形等纺丝技术开发的差别化产品。不仅改善了尼龙的性能 ,而且赋予尼龙更好的功能。特达 ○R具有良好的强度和韧性、优良的耐磨性、弹性回复性以及染色性能 ,是用于户外运动服的好面料。     

Replication of liner collapse phenomenon observed in hyperbaric type IV hydrogen storage vessel by explosive decompression experiments

An experimental design based on representative sample is described in order to reproduce the detachment and deformation of the inner polymer layer (called liner) of hyperbaric hydrogen storage vessels during the emptying step. It is the first step of a better understanding of the mechanisms involved in the creation of a liner collapse. Results showed that a hydraulic testing machine fitted with a pressure hydrogen chamber enables to create a liner collapse on small samples by explosive decompression experiments. Tomographic observations have revealed that the collapse appears at the polymer liner/composite interface in areas that are not sufficiently bonded, nor consistently. Determination of liner collapse amplitudes, assessed by tomography, has underlined that, under some specific conditions, the deformation of the liner is permanent even when hydrogen has completely desorbed from the sample. In addition to liner collapses, composite cracks were also highlighted.     

锦纶莱卡包覆纱拉伸性能与包覆度的关系

用一定规格的锦纶丝、莱卡长丝在空心锭纺纱机上纺制了一系列不同包覆度的锦纶莱卡包覆纱,并对其成纱性能进行了拉伸试验分析,得到了包覆纱断裂强力、断裂伸长率与包覆度之间的相应规律.