LDPE与LLDPE共混树脂薄膜的研究

将线性低密度聚乙烯(LLDPE)与低密度聚乙烯(LDPE)经过熔融共混、挤出吹制得一系列薄膜。分析了共混树脂的流变性能,研究了共混树脂的结晶性能,讨论了薄膜的力学性能和热稳定性能。结果表明:纯树脂和共混树脂熔体都是假塑性流体,通过升温同样可以降低共混树脂的表观黏度,共混树脂薄膜的力学性能优于纯LDPE薄膜,LDPE质量分数为70%的薄膜热稳定性最佳。     

纳米抗菌LDPE包装膜的研究

将处理后的纳米TiO_2加入低密度聚乙烯(LDPE)中,通过双螺杆挤出机造粒得到抗菌母料,然后将抗菌母料与LDPE混合并挤出吹制抗菌LDPE薄膜,研究了薄膜的抗菌及力学性能。结果表明:采用该工艺制得的LDPE薄膜无毒、抗菌性能良好;随抗菌母料的增加(即纳米TiO_2的增加),LDPE薄膜的纵向拉伸强度和横向拉伸强度均有增加,抗菌母料质量分数由1%增加到5%时,抗菌薄膜的纵向拉伸强度由9.2 MPa提高至14.6 MPa;拉伸断裂应变略有下降。     

吹塑薄膜级LDPE LD608的应用性能

研究了管式法聚乙烯装置上开发的吹塑薄膜级低密度聚乙烯(LDPE)LD608的各项性能,并与LDPE1F7B进行了对比。结果表明:两者熔体流动速率相当,而LD608拉伸性能较高,加工适应性好;用LD608吹制的薄膜光学性能优良、开口性能好,更适用于复合基材膜及橡胶包装膜的加工,是优良的吹塑薄膜级LDPE树脂。     

LDPE农用耐候棚膜专用料的配方研究及工业化生产

研究了LDPE农用聚乙烯耐候棚膜专用料的配方及老化问题,介绍了选用母粒掺混法制备专用料的工艺路线。经人工加速老化和扣棚自然老化试验证明,用该专用料吹制的棚膜,其使用寿命可达1.5～2年,比普通膜寿命长3～4倍。     

淀粉粒径对微细化淀粉/LDPE共混体系降解性能影响

采用光降解、土埋降解和环境降解法，研究了不同粒径微细化淀粉／LDPE共混膜的降解性能。结果表明，淀粉粒径的降低促进LDPE的环境降解基体的形成，加速淀粉和LDPE的环境降解速度。微细化淀粉／LDPE共混体系的降解是环境促降解因子共同作用的结果。     

高速挤出涂覆专用树脂的工业开发

结合市场需求和低密度聚乙烯（LDPE）装置特点,开发了LDPE高速挤出涂覆专用树脂1C7A-1。确定了反应压力、反应温度、引发剂消耗量及链转移剂加入种类。生产的1C7A-1各项指标可满足市场需求,涂覆过程中的膜边缘稳定性得到提高,挤出复合时缩幅较小,且加工速度较高（大于280m/min）,最小涂覆厚度达到6μm,填补了国内无菌包装高速挤出涂覆树脂生产的空白。     

微细介入导管的挤出机头设计

针对一种材料为低密度聚乙烯（LDPE）、外径1．0mm、内径0．4mm、壁厚0．3mm的医用微细介入导管，设计了一种专用微管挤出机头，其特点是采用了整体芯棒、圆孔分流支架和双管机头结构，详细介绍了该挤出机头的设计过程。     

国内外信息

LDPE/PA6共混阻透薄膜江苏石油化工学院研制成将LDPE(低密度聚乙烯 ) ,PA6 (尼龙 6 )和PE - g -MAH(马来酸酐接枝聚乙烯 )等混合后加入单螺杆挤出机内 ,经熔融挤出吹塑制成LDPE/PA6共混阻透薄膜 ,其阻透性能比纯LDPE膜提高了 10倍以上。PE吹塑转光膜徐州塑料一厂在PE中添加转光母料及转光粉制成PE吹塑转光膜。据介绍 ,转光膜在保持PE膜的外观质量和物理力学性能的同时 ,具有明显的增温效应 ,可促进农作物早熟 ,提高作物质量。(以上由常州市和平北路 9号　汪焕心供稿 )工程塑料低温抗冲改性剂据“AdditivesforPolymers” ,2 0…     

PE膜用填充母料的研制

以CaCO_3为填料核,低密度聚乙烯(LDPE)为载体制得填充母料并应用于聚乙烯(PE)膜中.研究了不同种类偶联剂活化CaCO_3、CaCO_3与LDPE共混比和PE蜡的加入对填充母料的熔体流动速率(MFR)的影响,考察了填充母料在PE膜中的应用效果.结果表明,DL-411-D型铝酸酯偶联剂的活化效果较好;CaCO_3与LDPE为2∶1～3∶1时母料的MFR适于薄膜的挤出流延;母料应用于PE膜中可达到作为卫生材料的要求.     

mLLDPE/LDPE膜制备及蠕变性能的研究

利用农用膜共挤出设备制备了m LLDPE/LDPE膜,并通过自制蠕变仪测定了其蠕变性能。实验结果表明m LLDPE的加入增加了膜的柔性,增加载荷和升高温度都会导致复合膜蠕变增加。针对膜的m LLDPE含量、温度及载荷对膜的蠕变性能的研究,对实际生产有着重要的指导意义。     

LID组合措施在杭州低影响开发区项目中的应用研究——基于SWMM模型

结合杭州市低影响开发区对雨水控制的要求,运用SWMM模型模拟常规开发模式、组合LID设施、组合LID+蓄水池对雨洪控制的效果.研究结果表明,组合LID设施可以有效降低场地内洪峰流量、径流系数,并使场地在50 a重现期以下的降雨情况无溢流节点;组合LID+蓄水池可以控制杭州市100 a重现期2 h短历时降雨量的94.3％...     

Three Screw Extruder

电子、汽车、电机、电器、仪器、仪表、家电、通讯和军工等产品中，60％～80％的零部件，都要依靠模具成型。用模具成型的制件所表现出来的高精度、高复杂性、高一致性、高生产率和低消耗，是其他加工制造方法所无法比拟的。模具在很大程度上决定着产品的质量、效益和开发能力。     

Use of sterically stabilized polymer colloids as electrostatically-based liquid developers

Liquid immersion development (LID) of a latent electrostatic image has become established as an important alternative to dry toning during the past decade. In this development method, a charged, colloidally stable colored particle that is dispersed in a dielectric fluid undergoes electrophoresis under the influence of an applied field. These particles then neutralize a latent electrostatic image of opposite polarity, which resides on either a photoreceptor drum or on dielectric paper. This results in a hard copy of the latent image being obtained. In this paper we outline the physicochemical properties that are demanded of a liquid toner and describe an alternative approach to the preparation of a LID materials package. This new approach utilizes a nonaqueous polymer colloid as the vehicle, which when colored and charged, gives a LID toner. The advantage of nonaqueous dispersions is that the steric stabilizer is irreversibly attached to the particle. Since desorption of the stabilizer is not a problem, these materials are colloidally stable for an indefinite period of time. The particles were colored using both dyes and pigments. While neither approach was entirely satisfactory, the feasibility of coloring such particles was demonstrated. A positive charge was imparted to the particles by specific adsorption of the cation of a metal soap at the polymer–fluid interface. It was found that these experimental LID toners were able to develop a latent electrostatic image in a commercially available printer with the image being well fixed to the paper. While this approach has not been optimized, it appears to be an attractive route for preparing novel LID developers.     

Gas permeation and temperature effects in laser-induced delamination

Laser-induced delamination (LID) is a technique aimed at measuring the work of adhesion of thin polymer coatings on metal substrates. A laser pulse is used to create a blister that initiates delamination of the film under pressure. The stress fields in the blister wall and the work of adhesion of the interface are determined using a linear elastic model.In this paper we discuss validity of the LID results addressing permeation of gas through the blister wall and the initial high temperature of the substrate. A procedure to account for the effect of gas permeation in the calculations of the work of adhesion is proposed. Permeation of gas is also considered under compressive and tensile in-plane stresses. Modeling of the permeation process demonstrates a good agreement with the experiment.At early stage of the blister formation the metal substrate and the blister gas experience high temperatures. The time scales of the cooling processes are estimated. Possible effects of the high temperatures on the permeation of gas and on the process of delamination are discussed.     

全水发泡中高密度超软聚氨酯泡沫的制备

采用软化剂与降低TDI指数相结合的方法制备了中等密度的超软聚氨酯泡沫,泡沫性能和当前的软化剂与二氯甲烷结合体系的相当。使用自制聚醚多元醇,全水发泡,制备了高密度超软PU泡沫,25％压陷硬度25～38N,65％／25％压陷比大于2．8。     

EFFECT OF OPERATING CONDITIONS ON GAS HOLDUP IN SLURRY BUBBLE COLUMNS WITH A FOAMING LIQUID

This work presents experimental data on gas holdup in slurry bubble columns with a foaming liquid. The effects of solids concentration, solid particle size, superficial phase velocities and column dimensions on the gas holdup are analyzed. At low superficial gas velocities (less than 4cm/s), for which the liquid does not foam, the presence of solids with small particle size does not affect the gas holdup whereas solids with large particle size induce foam formation and thus their presence increases the gas holdup. In the foaming regime, an increase of solids concentration decreases the gas holdup. The operating mode has a strong effect on the gas holdup: the semi-batch operating mode (stagnant liquid-solid suspension) increases the ability of the liquid to foam with respect to the continuous mode. Regarding the effect of column dimensions, the results presented show that the height of the bubble column does not affect at an appreciable extent the gas holdup in the range 6 < LID < 12. At high gas velocities (greater than 6 cm/s) the gas holdups obtained in a 30 cm-internal diameter column are the same as those measured in a 10 cm-internal diameter column.     

酚醛树脂热降解动力学研究

用热失重非等温法对不同甲醛,苯酚魔鬼洋比的酚树脂进行了热降解动力学研究。结果表明,甲醛,苯酚摩尔比为１．５时,酚醛树旨的热发活化能最高。耐热性最好。     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.     

锂云母珠光颜料在陶瓷釉料中的性能研究

通过白度和反射率对珠光颜料在陶瓷釉料中的着色力和珠光光泽进行了表征,探讨了PH值、水浴温度、锂云母:TiO2比例和煅烧温度对所制备的珠光颜料在制品白度和反射率的影响。XRD分析结果表明:当随着锂云母:TiO2比例增加(包覆次数的增加)时,白云母晶相和金红石相发生了较大变化,从而影响着釉面的白度和反射率。结果表明当锂云母:TiO2为100:62时,通过EDS测定并计算出TiO2的包覆率约达到22.12%。其釉面效果达到最优:白度为82%,反射率为45.7%