聚己内酰胺切片中可萃取物含量的影响因素分析

本文综述了各种因素对聚己内酰胺中可萃取物含量的影响。聚己内酰胺切片中的可萃取物在前纺的熔融和纺丝过程中会变成气体蒸发出来,不仅造成熔体挤出成形时产生毛丝,妨碍成形过程的正常进行,而且恶化工作条件。影响切片中可萃取物的含量的因素有切片的粒径、萃取温度、萃取时间、浴比(萃取水流量)和浓度梯度等。对影响聚己内酰胺切片中可萃取物含量的因素进行分析,为实际生产中增强纤维的机械强度、获得更高质量的纤维材料提供可行性经验。     

影响聚己内酰胺切片质量的主要因素

以原材料切片为研究侧重点,通过试验分析不同切片原材料特性对聚己内酰胺质量造成的影响。具体试验分析中主要考虑切片特性包括黏度、含水率、二氧化钛含量等,根据试验分析可知,实际聚己内酰胺生产中切片相对黏度、切片含水率（质量分数）和包装储存切片含水率（质量分数）应分别控制为2.4～2.8、0.03%～0.04%和0.04%,二氧化钛含量（质量分数）则控制在较低水平。     

聚己内酰胺切片生产中干燥工艺的研究

将干燥技术应用于大型的实际生产中,解决了以己内酰胺为原料生产聚己内酰胺的提高生产负荷过程中出现的黏度降低现象,并确定了干燥过程中氮气的流速和温度的最佳值。     

聚N-乙烯基己内酰胺的合成及放大

聚N-乙烯基己内酰(PNVCL)是目前应用最多,效果较好的新型天然气水合物动力学抑制剂之一,是传统热力学抑制剂的优良替代品。以甲醇(AM)为溶剂,偶氮二异丙基咪唑啉盐酸盐(AIBI)为引发剂,N-乙烯基己内酰胺(NVCL)为单体,聚合反应得到聚N-乙烯基己内酰胺(PNVCL),考察了反应温度、时间、溶剂量等合成条件对产品分子质量M_n及产率的影响,确定了合理的合成工艺。结果表明:当反应投料比m(NVCL)∶m(AIBI)∶m(AM)=10∶0.03∶19.8,体系温度为65℃,反应时间6 h,小试产率可达95.4%。依据小试条件进行了放大实验,讨论并确定了最佳放大工艺条件,即:m(NVCL)∶m(AIBI)∶m(AM)=10∶0.03∶21,体系温度65—68℃,反应时间5—6h,PNVCL收率为93.4%,具有良好的放大效果。     

聚己内酰胺注塑专用料现状与进展

介绍了聚己内酰胺注塑专用料的特点、国内外产品现状和最新进展,并建议生产企业重视注塑专用料的开发。     

影响聚己内酰胺切片含水率的因素探讨

为使聚己内酰胺切片的含水率达到纺丝的要求，对其干燥的时间为20-30小时，干燥的温度为110—130℃，干燥用氮气的露点应控制在10—12℃。     

银离子抗菌聚己内酰胺纤维的研制及开发

主要介绍银离子抗菌聚己内酰胺纤维的制造方法、设备、原料及纺丝工艺。如抗菌母粒的选择,纺丝温度,纺丝组件,纺丝油剂及上油率,卷绕速度。采用高速纺丝法工艺路线成功开发出银离子抗菌聚酰胺纤维。     

芳纶浆粕与聚己内酰胺复合的初步研究

对芳纶浆粕与聚己内酰胺复合进行了初步研究，实验表明，随芳浆粕含量的增加，复合材料的断裂伸长率和缺口冲击强度下降，拉伸屈服强度增加，拉伸断裂强度先降后增，芳浆粕是聚己内酰胺的α成核剂，复合材料的维卡热变形温度大幅度提高，熔体粘度增加，但粘流活化能不变。对芳纶浆粕进行浸渍处理可提高共混效果。     

聚己内酰胺切片的热学及流变性能研究

借助热分析技术和毛细管流变仪,分别对两种全消光聚己内酰胺纺丝切片的热学性能和流变性能进行了研究和分析,旨在为熔融纺丝生产工艺控制提供一定的理论依据。结果表明:两种切片在纺丝温度范围内热降解程度均可满足正常纺丝,A公司的切片较易发生结晶;剪切速率越大,熔体受温度的影响越小,稳定性越好;在相同剪切速率下,A切片的黏流活化能较B切片的高,表观黏度对温度的依赖性大。     

聚己内酰胺固相缩聚工艺

对采用固相缩聚从低黏度聚己内酰胺树脂制备高黏度聚己内酰胺树脂的工艺条件进行了研究。研究结果表明，催化剂Z能有效地提高增黏速率，控制其用量和合适的工艺条件可以制得所需黏度的聚己内酰胺树脂。     

多晶硅生产中硅芯氧化问题探究

改良西门子法生产多晶硅中硅芯是多晶硅生长的载体,硅芯氧化会降低多晶硅产品品质,硅芯氧化的产品对下游铸锭、直拉均有不同程度的影响。目前硅芯氧化是影响多晶硅产品质量的一大问题。分析了硅芯氧化机理,针对相关因素开展了试验,提出了降低硅芯氧化率的措施。     

氧化塘水体富营养化及其综合防治

针对氧化塘水体富营养化,介绍了氧化塘水体富营养化的发生机理、影响因素及其危害,探讨了防治措施,并展望了未来的研究趋势。     

甲苯氧化制苯酚工艺及经济评价

介绍了甲苯氧化制苯酚的原理和工艺，并对该工艺进行了经济分析，结果表明：该工艺不仅可以合理地利用滞销的甲苯，而且流程简单，产品成本低，具有广阔的前景。     

Capabilities of different cooking oils in prevention of cholesterol oxidation during heating

The potential of various cooking oils to prevent cholesterol degradation and/or oxidation, as measured by the production of 7-ketocholesterol during heating at different temperatures, was studied using a cholesterol model system. In the control group (without cooking oil), cholesterol was relatively stable, and 73% of its initial concentration was present after 30 min of heating at 125°C. Less than 30 and 10% of cholesterol remained at 150 and 175°C after 30 min, respectively, and 10% at 200°C after 10 min. In the treatment group, cholesterol mixed with corn, canola, soybean, or olive oil had significantly improved thermal stability. More than 60 and 40% of cholesterol remained at 150 and 175°C after 30 min, respectively. In the control group, 7-ketocholesterol was produced when samples were heated above 150°C, and levels increased consistently during 30 min of heating. At 175 or 200°C, the level of 7-ketocholesterol did not increase further after reaching the highest level after 10 min of heating. 7-Ketocholesterol is not stable above 175°C, and its degradation rate could be much faster than its production at 200°C. 7-Ketocholesterol was not found in samples of cholesterol mixed with corn oil or laboratory-prepared soybean and rice bran oils until the heating temperature was raised to 175°C for 20 min. The levels of 7-ketocholesterol in those treatment groups were greater than that in the control group at 175°C for 30 min. These oils may increase the thermal stability of 7-ketocholesterol and retard its degradation rate.     

Chemical and biological oxidation of Pinus pinaster lignin of the production of vanillin

Oxidation of kraft black liquor with 14·39% solids content, obtained by cooking of Pinus pinaster wood, was studied by three different process; chemical oxidation with molecular oxygen at 120–138°C (oxygen partial pressure ≈ 0·15 MPa); biological (enzymatic) oxidation; and combined oxidation (in the sequence: chemical + enzymatic). Lignin degradation was followed by high pressure liquid chromatography (HPLC). Production of low molecular weight compounds, e.g. vanillin, was monitored by gas chromatography (GC). Chemical oxidation produced about 1.5 g of vanillin per dm³ of liquor (0·904 g per 100 g of solids). Biodegradation products had molecular weights near to that of vanillin and mainly around 100 daltons, but vanillin was not detected. In the combined oxidation process, vanillin was consumed with a concomitant reduction of the HPLC peak.     

影响烧碱蒸发生产能力的因素探讨

计算并分析了各种因素对蒸发装置、传热系数、传热面积、传热温差的影响。提出了为提高烧碱蒸发装置生产能力、改进措施和今后的打算。     

Hydrogen production from partial oxidation and reforming of DME

Hydrogen production from partial oxidation and reforming of dimethyl ether (DME) was investigated with a fixed bed continuous-flow reactor. H₂ yield of over 90% was obtained with 100% DME conversion at 700 °C over Pt/Al₂O₃+Ni–MgO dual catalyst bed, while keeping CH₄ yield at low level. Such results indicated that partial oxidation and reforming of DME to produce hydrogen at high temperature is possible and effective.     

次氯酸钠氧化法预处理乙炔清净废水的研究

采用次氯酸钠(Na Cl O)氧化法对乙炔清净废水进行预处理。分别考察了废水的p H、温度、Na Cl O溶液加入量和反应时间对废水中NH3-N和COD去除率的影响,用正交实验的方法确定了NH3-N的最佳处理条件。结果表明,Na Cl O溶液加入量对NH3-N去除率的影响最大,其次是废水的温度和p H,反应时间的影响最小,对于200 m L的废水,最佳处理条件为:废水的p H为8、温度为50℃、Na Cl O溶液加入量为5.5 m L、反应时间为5 min。此时NH3-N、COD和TN的去除率分别为99.8%、51.9%和90.9%,游离氯的剩余量很低。