微发泡聚丙烯复合材料发泡行为研究

以PP(聚丙烯)为基体材料,分别添加发泡剂母粒、发泡剂和助剂母粒及发泡剂、助剂、成核剂母粒,在二次开模条件下注塑制备微发泡PP复合材料,分析了发泡助剂及成核剂对微发泡复合材料发泡行为的影响规律。结果表明,添加发泡助剂以后,PP体系的发泡质量得到明显改善;助剂和成核剂同时添加,微发泡PP体系的发泡质量最好,泡孔平均直径为26.79μm,泡孔密度达到4.76×106个/cm3。     

成核剂对聚丙烯微发泡行为及力学性能的影响

将自制的发泡母料添加到共聚聚丙烯(PP)中,采用化学发泡注塑工艺制得微发泡材料。通过SEM和TGA分析,研究了不同成核剂制得的发泡母料对PP微发泡材料力学性能和泡孔行为的影响。结果表明:发泡母料含量为5%时,制得的发泡PP复合材料性能优异;以硫酸钙作为成核剂时,所得制品泡孔直径较小,且均匀性最好。     

成核剂对PP发泡行为和力学性能影响

采用化学发泡注射成型技术制备了发泡聚丙烯(PP)复合材料,研究了不同成核剂(NA)含量对其发泡行为和力学性能的影响。结果表明:NA的加入为泡孔成核提供了大量的成核位点,有效改善了发泡PP复合材料的泡孔结构、尺寸分布和泡孔密度;当NA质量分数为5‰时,发泡材料泡孔平均直径最小约125μm,泡孔密度最大约2.54×10~5个/cm~3,泡孔尺寸分布较好。另一方面,随着NA含量的增加,发泡PP复合材料的拉伸强度、弯曲强度和弯曲模量呈增加趋势。     

成核剂对聚丙烯釜压发泡的影响

用超临界二氧化碳（CO2）釜压发泡的方法,研究了成核剂类型、成核剂粒径以及成核剂添加量对聚丙烯（PP）发泡材料泡孔结构的影响。结果表明,用碳酸钙（CaCO3）作成核剂时PP泡沫的泡孔完整性高,泡孔尺寸分布均匀,且发泡倍率比添加蒙脱土及滑石粉时的要大;成核剂粒子粒径越小,体系的成核点越多,发泡时产生的气泡核越多,所得到的PP泡沫的泡孔密度越大,但是由于纳米碳酸钙（nano-CaCO3）更容易出现团聚现象,直接导致最终发泡制品产生泡孔破裂以及发泡倍率的降低;成核剂CaCO3的添加量为3份时,与添加1份和5份相比,可得到发泡倍率更高,泡孔密度更大的PP泡沫。     

有机笼状成核剂/聚丙烯复合发泡材料的性能研究

以6元半瓜环(HQ[6])作为异相成核剂,以偶氮二甲酰胺(AC)为发泡剂,通过注塑成型工艺制备聚丙烯(PP)复合发泡材料。利用扫描电镜研究了复合发泡材料的泡孔形貌,利用差示量热扫描仪等测试探讨了HQ[6]对PP发泡行为的改善机理。结果证明,HQ[6]可以作为有机成核剂应用于PP发泡材料的制备。     

成核剂BN对P34HB发泡材料性能的影响

将不同用量的成核剂(BN)添加到聚3-羟基丁酸-4-羟基丁酸酯(P34HB)基体中,采用熔融模压法制备了P34HB/BN发泡材料。通过扫描电镜(SEM)探究了BN用量对发泡材料密度、泡孔尺寸及力学性能的影响。结果表明:当BN用量为3份时,发泡材料的力学性能最佳,密度最低,材料内部泡孔大小及分布均匀。     

成核剂含量对PS发泡复合材料泡孔形态的影响

在聚苯乙烯(PS)加入不同含量的成核剂,用自行研制的动态发泡模拟机研究了成核剂含量对PS发泡复合材料泡孔形态的影响。研究发现,成核剂有助于PS发泡材料形成大量成核点,泡孔成核更容易;并且PS中成核剂的含量不同会影响泡孔的形态,在发泡过程中尽量促进成核剂的分散,使体系内聚合物熔体、发泡剂和成核剂尽量均化,可以增加成核点数量并使泡孔分布均匀,改善泡孔形态。     

β成核剂对聚丙烯发泡材料的结晶行为和发泡性能的影响

在聚丙烯(PP)中加入β成核剂(TMB-5),以超临界二氧化碳(CO2)作为发泡剂,用高压发泡釜对其进行间歇发泡。研究β成核剂用量、饱和温度、饱和压力对β成核/PP发泡材料的结晶和发泡性能的影响。结果表明,β成核剂有效促进了β晶的形成,发泡材料中β晶相对含量最高可达到92.4%,但增大饱和压力却会抑制β晶产生。β成核剂同时起到异相成核作用,使泡孔成核更容易,制得的样品发泡性能较好。另外,饱和温度的升高会使PP熔体强度降低,导致泡孔的尺寸增大、密度减小;而随着饱和温度降低,饱和压力升高,气体在熔体中的溶解度增大,泡孔成核数量增多,使泡孔密度增大、泡孔尺寸减小。饱和压力为22 MPa时,泡孔密度可达2.72×108个/cm3。     

二次开模距离对微发泡聚丙烯材料发泡行为的影响

采用化学发泡注塑成型技术,在二次开模条件下制备微发泡聚丙烯(PP)材料;通过热力学分析法研究了二次开模距离对PP微发泡材料发泡行为的影响。结果表明:二次开模距离能有效地控制PP材料的发泡过程,二次开模距离越小,体系的发泡过程越容易自发进行。当二次开模距离L=5.3 mm时,体系中的吉布斯自由能小于零,发泡过程不可能自发进行;二次开模距离L=4.3 mm时,PP体系的发泡质量最理想,泡孔平均直径为21.6 m,泡孔密度为5.63×106个/cm3,能够获得泡孔细小、均匀的微发泡PP材料。     

泡孔结构参数对微孔发泡聚丙烯力学性能影响

采用化学发泡法制备聚丙烯(PP)微发泡材料,研究了不同泡孔结构参数对其力学性能的影响。结果表明:微孔发泡PP材料的拉伸强度和冲击强度随着表观密度的增加而提高;随着泡孔尺寸和泡孔尺寸分散度的增大,发泡PP材料的拉伸强度和冲击强度都显著下降。     

乙烯酮(双乙烯酮)下游产品废水的治理技术

乙烯酮(双乙烯酮)是十分重要的化工中间体,其下游产品较多。江苏某化工厂开发生产乙烯酮(双乙烯酮)下游产品三十多个,年生产规模三万多吨,是国内以乙烯酮(双乙烯酮)为中间体生产精细化学品的综合骨干企业。针对乙烯酮(双乙烯酮)下游产品废水特点,该厂结合企业实际,开展了产品优化,结构调整,清洁生产,资源循环利用,节水降耗等工作,从源头削减了污染物的生产。同时投资二千多万元新建预处理装置三套,6000m3/d废水生化处理装置一套,使全厂乙烯酮(双乙烯酮)下游产品的废水得到了有效的治理。     

A study of miscibility of blends of polybutadienes of varying microstructure

The miscibility of various amorphous polybutadienes with mixed microstructures of 1,4 addition units (cis, 1,4 and trans 1,4) and 1,2 addition units have been investigated. The studies here involved optical transparency, differential scanning calorimetry, and small angle light scattering. It was found that a 90 percent (cis) 1, 4 addition polybutadiene was immiscible with high (91 percent) 1,2 addition polybutadiene. Reduction of the 1,2 content to 71 percent induced an upper critical solution temperature (UCST) with the cis 1,4 polymer. Polybutadienes with 50 percent and 10 percent 1,2 contents were miscible above the crystalline melting temperature of the cis 1,4 polybutadiene. Immiscibility of the 91 percent 1,2 addition polymer was also found with a 10 percent 1,2 polybutadiene. The latter polymer also exhibits an UCST with the 71 percent 1,2 polymer. The results are used to interpret the characteristics of blends of polybutadienes of varying microstructure.     

几种乙炔加压设备性能的比较

阐述并比较了几种加压设备在乙炔加压清净过程中的性能和特点。     

粉煤灰中烧失量检测的不确定度分析

以F类粉煤灰为例,详细介绍了测定粉煤灰中烧失量的步骤、计算数学模型、影响测量不确定度的因素以及各项测量不确定度分量评定,人员、设备、材料、方法、环境都是影响测量不确定的因素。     

生物油的成分分析及物性测定

以添加FeCl2的ZnCl2-KCl混合熔盐裂解纤维素和秸秆,制得生物油。采用傅立叶变换红外光谱法和气相色谱-质谱法分析生物油的成分。结果表明,生物油中成分复杂,含有氧元素、多种有机化合物,主要包括酮类、醛类、酚类及羧酸类等。测定了20～80℃生物油的密度和粘度,发现生物油的密度与温度呈较好线性关系,而生物油的粘度均大于水的粘度,且不同熔盐体系对秸秆生物油的粘度无较大影响。     

分解炉扩径的技术改造

我厂3号回转窑(Φ4m×60m)生产线在1996年年底由SP窑(产量912t/d)改为NSP窑(产量1320t/d),预分解系统为四级旋风预热器带离线式分解炉     

Process of acceleration of filtration of viscose

Conclusions It is significant that the purification on a single passage of viscose through porous ceramic corresponds to the result of a two-stage filtration of it in industrial filter-presses with standard fillings.Kiev Combine. Kiev Technological Institute of Light Industry. Translated from Khimicheskie Volokna, No. 3, pp. 20–22, May–June, 1969.     

Effect of degree of deacetylation of chitosan on the kinetics of ultrasonic degradation of chitosan

The objective of the study was to explore the effect of the degree of deacetylation (DD) of the chitosan used on the degradation rate and rate constant during ultrasonic degradation. Chitin was extracted from red shrimp process waste. Four different DD chitosans were prepared from chitin by alkali deacetylation. Those chitosans were degraded by ultrasonic radiation to different molecular weights. Changes of the molecular weight were determined by light scattering, and data of molecular weight changes were used to calculate the degradation rate and rate constant. The results were as follows: The molecular weight of chitosans decreased with an increasing ultrasonication time. The curves of the molecular weight versus the ultrasonication time were broken at 1‐h treatment. The degradation rate and rate constant of sonolysis decreased with an increasing ultrasonication time. This may be because the chances of being attacked by the cavitation energy increased with an increasing molecular weight species and may be because smaller molecular weight species have shorter relaxation times and, thus, can alleviate the sonication stress easier. However, the degradation rate and rate constant of sonolysis increased with an increasing DD of the chitosan used. This may be because the flexibilitier molecules of higher DD chitosans are more susceptible to the shear force of elongation flow generated by the cavitation field or due to the bond energy difference of acetamido and β‐1,4‐glucoside linkage or hydrogen bonds. Breakage of the β‐1,4‐glucoside linkage will result in lower molecular weight and an increasing reaction rate and rate constant. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3526–3531, 2003