泡沫塑料主要力学性能及其力学模型

描述发泡塑料力学性能的模型,讨论了普通发泡塑料的力学性能以及它和发泡塑料密度的关系。并且比较了硬质聚氨酯(RPUR)和聚氯乙烯(PVC)泡沫塑料的主要力学性能随密度的变化。最后介绍了微孔发泡塑料的几项优良的力学性能。     

超临界CO_2制备微孔聚碳酸酯及其泡孔特性研究

采用超临界微孔发泡技术制备出一系列聚碳酸酯微孔泡沫塑料,通过扫描电子显微镜、密度测试等方法研究了发泡温度和发泡时间对聚碳酸酯微孔泡沫塑料泡孔特性和体积密度的影响。结果表明,在测试范围内,随发泡温度的升高,泡孔密度增加,泡孔孔径先增加后降低,体积密度降低;随发泡时间的增加,泡孔密度和孔径均增加,体积密度降低。     

自由发泡聚氨酯硬泡密度理论计算及其应用

通过对聚氨酯硬质泡沫塑料发泡机理的分析，提出了泡沫密度的理论计算模型，建立了泡沫密度与发泡剂量等因素的关系式，并就其实际应用进行了探讨。     

环戊烷-异戊烷发泡体系在冰箱生产中的应用

介绍了环戊烷－异戊烷发泡聚氨酯硬泡体系在冰箱生产中的应用,并从发泡工艺及性能上与环戊烷发泡体系进行了比较,结果表明,与环戊烷发泡体系相比,环戊烷－异戊烷发泡体系在箱体的灌注量减少了7％,泡沫密度降低12％,同时泡沫的尺寸稳定性好,且密度较环戊体系均匀,仅泡沫的导热系数略微升高,导热系数为21.8mW/(m.K).     

冰箱用环戊烷聚氨酯发泡体系流动性的研究

探讨了冰箱用硬质聚氨酯泡沫塑料发泡体系中催化剂、匀泡剂等因素对物料流动性的影响。结果表明,催化剂对环戊烷发泡体系的流动性影响较大,不同类型催化剂在恰当的用量匹配下可使发泡物料获得较佳的流动性,在物料的爬高性能与泡沫密度分布均匀性方面均有改善;匀泡剂对环戊烷体系的流动性影响主要体现在泡沫密度分布方面,当匀泡剂用量为2．2份时,发泡体系的密度分布最均匀。     

三乙醇胺对硬质聚氨酯泡沫塑料性能的影响研究

制备了孔径约0.5 mm的全水发泡硬质聚氨酯泡沫塑料。研究了三乙醇胺(TEA)用量对聚氨酯泡沫塑料发泡时间、表观密度、导热性能、力学性能等的影响规律。TEA是体系反应的催化剂,随着TEA含量增大后发泡时间变短。TEA含量少于7份时,发泡反应强于凝胶反应,制品泡孔直径随着其含量增加而变大,表观密度、热导率、压缩强度、拉伸强度和弯曲强度下降,断裂伸长率上升。TEA含量大于7份时,交联作用占主要地位,制品泡孔直径随着其含量增加而变小,表观密度、热导率、压缩强度、拉伸强度和弯曲强度上升。热失重分析也表明TEA含量大于7份后产生了交联作用。     

硬质聚氨酯泡沫塑料模塑成型压力研究

采用正交实验，初步探索了模具温度、原料温度、催化剂用量、发泡剂用量、匀泡剂用量、异氰酸酯指数对硬质聚氨酯泡沫塑料模塑成型时发泡压力的影响规律。在此基础上，进一步研究了当密度不同时，发泡剂对发泡压力的影响，并采用回归分析的方法获得了硬质聚氨酯泡沫塑料模型成型发泡压力（y）、泡沫塑料模腔内发泡密度（x‘）和发泡剂的用量（x）三者之间的数学关系，结果为y=(1.2181x‘-0.0991)x 0.2975x‘-0.0966。     

环戊烷—异戊烷混合烃发泡技术在冰箱生产中的应用

介绍碳氢发泡新一代替代技术 :环戊烷 -异戊烷发泡聚氨酯硬泡技术在冰箱生产中的应用情况 ,并从发泡工艺及性能上与环戊烷发泡体系进行了比较。结果表明 ,与环戊烷发泡体系相比 ,环戊烷 -异戊烷发泡体系加工工艺性良好 ,在冰箱发泡灌注量上减少了 7% ,泡沫密度降低 10 % ,同时泡沫的尺寸稳定性好 ,且密度分布较环戊烷发泡体系均匀 ,仅泡沫热导率在常温下测试略微升高 ,导热系数约为 2 1.5mW /m·K ,但泡沫材料在低温状态下保温性能良好 ,使整机能耗维持原有水平 ,可降低发泡生产成本。     

催化剂DABCO8154对硬质聚氨酯泡沫塑料性能的影响

采用一步法合成聚氨酯硬质泡沫塑料,考察了催化剂DABCO8154对聚氨酯塑料发泡体系的发泡时间、表观密度、热稳定性能、力学性能等的影响。随着DABCO8154用量的增加,发泡时间缩短,表观密度先下降后提高。压缩性能、弯曲性能随着DABCO8154含量增加逐渐降低。随着DABCO8154的加入,制品热稳定性提高。     

模压法制备LLDPE高发泡塑料的研究

研究了用模压法制备线型低密度聚乙烯(LLDPE)的高发泡泡沫塑料。探讨了发泡剂、交联剂、促进剂以及LLDPE与低密度聚乙烯(LDPE)的配比对高发泡塑料的表观密度、回弹率、压缩永久变形和压缩强度的影响。实验结果表明,在合适的配方和工艺条件下,以LLDPE为主,配以少量的LDPE树脂可制得高发泡塑料。     

A study of composite foams for diving suits subjected to high hydrostatic pressure

In order to obtain foams possessing flexibility and at the same time heat insulation under high hydrostatic pressure, composite foams with spherical rigid foams filled in flexible rubber foam at certain intervals were prepared and their thermal conductivity and flexural rigidity were studied. The following points were found: (1) With a unit model having a spherical rigid foam in the middle, the thermal conduction of a composite foam was analyzed under the conditions of steady one-dimensional heat flow. Theoretical equations giving overall coefficients of heat transmission under atmospheric and hydrostatic pressures were obtained, and the adequacy of these theoretical equations was confirmed by the measurement of overall coefficients of heat transmission of composite foams in an apparatus so constructed as to allow heat conduction experiments under pressures ranging from atmospheric to the hydrostatic pressure corresponding to 100-m depth in water. (2) The effect of the filled spherical rigid foams on heat insulation is notable under hydrostatic pressures corresponding to a 20-m depth or more in water. Under the hydrostatic pressure corresponding to a 100-m depth in water, the coefficient of heat insulation of the most closely filled composite foam used in the experiment was approximately 35% larger than that of the unfilled foam, while the theoretical most closely filled composite foam gives an approximately 110% increase. (3) Under the hydrostatic pressure corresponding to a 100-m depth in water, the flexural rigidity of the most closely filled composite foam used in the experiment was approximately one half that of an unfilled foam of the same heat insulating property.     

硬质泡沫塑料耐热性测试方法研究

在分析泡沫塑料受热行为的基础上,对硬质聚甲基丙烯酰亚胺(PMI)、聚氨酯(PUR)、酚醛(PF)及交联硬质聚氯乙烯(PVC)泡沫塑料进行了差示扫描量热(DSC)、热失重(TG)、静态热机械分析(TMA)、马丁耐热温度、热变形温度(HDT)、尺寸稳定性、高温压缩蠕变、均匀受压时高温体积收缩率等热性能测试。研究表明,DSC,TG,TMA等热分析仅反映了硬质泡沫塑料中聚合物部分的耐热性,不能反映硬质泡沫塑料的整体耐热性,也不能反映密度对耐热性的影响;依照GB/T 1699–2003测试马丁耐热温度的方法和依照GB/T 1634–2004测试HDT的方法不适用于硬质泡沫塑料耐热性的测试;依照GB/T 8811–2008测试的尺寸稳定性和依照DIN 53424–1978测试的HDT可以初步作为硬质泡沫塑料耐热性的表征方法;依照GB/T 15048–1994测试高温压缩蠕变的方法以及依据固化工艺条件测试均匀受压时的体积收缩率的方法能够更加准确地表征硬质泡沫塑料的实际耐热性。     

Starch,Sucrose, and Rezol® IL800 as Density Modifiers for Polyurethane Rigid Foams Formulated by Recycled Polyol

Waste polyurethane rigid foam (PUF) is recycled by the glycolysis process. The recycled product is used in a polyol blend, applied in a new foam formulation. Polyurethane rigid foams formulated by recycled polyols are highly dense compared to rigid foams formulated by virgin polyols. As these foams are mostly used in insulation, they make an extra mass to the main product or system that is insulated. Therefore, it is important to decrease their density as much as possible.

Some density modifiers such as starch, sucrose, and REZOL^® IL800 were investigated to recognize their effect on PUF's density.     

Fabrication of Low-Density Ferrous Metallic Foams by Reduction of Chemically Bonded Ceramic Foams

Closed cell ferrous foams were fabricated using a chemically bonded oxide ceramic foam precursor. The major constituent of the ceramic foam precursor was iron oxide (Fe₂O₃), which was mixed with various foaming/setting additives. The density of the foam was modified by varying the ambient pressure under which foaming was carried out. Further, a magnesium–ammonium phosphate-based cement system was utilized to promote more rapid setting times and hence minimize foam collapse. The oxide foam was then reduced by heating at 1240°C in a non-flammable hydrogen/inert gas mixture to obtain metallic foams. The relative density of samples foamed under a reduced pressure (∼380 Torr) was 0.13±0.006, which is the lowest value reported to date for a closed cell ferrous foam. A relative density of 0.21±0.01 was achieved for samples foamed under atmospheric pressure. With regard to the foam morphology, the average cell diameter was 1.41±0.6 mm for the low-density (LD) foams, and 0.96±0.2 mm for the high-density (HD) foams. The iron foams were tested in compression and yielded an average compressive strength of 11±1 and 19±4 MPa for the LD and HD foams, respectively. A comparison based on a bending strength performance index showed that the properties of the ceramic–precursor-derived foams compared favorably with those of steel foams fabricated by other techniques.     

硅藻土填充聚氨酯硬泡的性能研究

用硅藻土粉体作为填料,采用全水发泡剂自由发泡制备了聚氨酯硬泡。通过热重分析（TGA）、扫描电子显微镜（SEM）、氧指数仪和万能实验机,研究了硅藻土对聚氨酯硬泡热稳定性、泡孔结构、极限氧指数（LOI）和力学性能的影响。结果表明,硅藻土使聚氨酯硬泡的孔径和密度增大,能提高聚氨酯硬泡的热稳定性、LOI、强度和模量。     

Foaming of rigid PVC/wood‐flour composites through a continuous extrusion process

The effects of chemical foaming agent (CFA) types (endothermic versus exothermic) and concentrations as well as the influence of all‐acrylic processing aid on the density and cell morphology of extrusion‐foamed neat rigid PVC and rigid PVC/wood‐flour composites were studied. Regardless of the CFA type, the density reduction of foamed rigid PVC/wood‐flour composites was not influenced by the CFA content. The cell size, however, was affected by the CFA type, independent of CFA content. Exothermic foaming agent produced foamed samples with smaller average cell sizes compared to those of endothermic counterparts. The experimental results indicate that the addition of an all‐acrylic processing aid in the formulation of rigid PVC/wood‐flour composite foams provides not only the ability to achieve density comparable to that achieved in the neat rigid PVC foams, but also the potential of producing rigid PVC/wood‐flour composite foams without using any chemical foaming agents.     

Water-blown rigid and flexible polyurethane foams containing epoxidized soybean oil triglycerides

Both rigid and flexible water-blown polyurethane foams were made by replacing 0–50% of Voranol® 490 for rigid foams and Voranol® 4701 for flexible foams in the B-side of foam formulation by epoxidized soybean oil. For rigid water-blown polyurethane foams, density, compressive strength, and thermal conductivity were measured. Although there were no significant changes in density, compressive strength decreased and thermal conductivity decreased first and then increased with increasing epoxidized soybean oil. For flexible water-blown polyurethane foams, density, 50% compression force deflection, 50% constant force deflection, and resilience of foams were measured. Density decreased first and then increased, no changes in 50% compression force deflection first and then increased, increasing 50% constant force deflection, and decreasing resilience with increase in epoxidized soybean oil. It appears that up to 20% of Voranol® 490 could be replaced by epoxidized soybean oil in rigid polyurethane foams. When replacing up to 20% of Voranol® 4701 by epoxidized soybean oil in flexible polyurethane foams, density and 50% compression deflection properties were similar or better than control, but resilience and 50% constant deflection compression properties were inferior. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

低CFC发泡工艺

介绍了减少75％CFC－11的聚氨酯硬质泡沫塑料的发泡工艺，对影响工艺参数和泡沫性能的一些因素进行了讨论。该泡沫的密度与导热系数较全CFC－11发泡泡沫均增大15％～20％。     

Smart polymer recycling: Synthesis of novel rigid polyurethanes using phosphorus‐containing oligomers formed by controlled degradation of microporous polyurethane elastomer

This article describes a new approach for the recycling of microporous polyurethane elastomers by Tris(1‐methyl‐2‐chloroethyl) phosphate‐induced degradation. The phosphorus‐containing degradation products formed are transformed into reactive intermediates by reaction with propylene oxide and are used for the preparation of rigid polyurethane foams. These new phosphorus‐containing materials have higher density and better mechanical properties compared to the standard rigid polyurethane foams. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

催化剂对废旧PU硬泡回收再利用的影响

用含有小分子醇的交联剂和催化剂使废旧聚氨酯（PU）硬泡进行降解能够获得多元醇，将降解料与聚醚多元醇、催化剂和发泡剂共混以制备白料，然后与黑料异氰酸酯混合均匀，得到再生PU硬泡。通过对降解产物的黏度、羟值以及获得的再生PU硬泡材料的密度、强度、吸水率、热稳定性、扫描电子显微镜、红外光谱和热失重等进行测试分析，得出了催化剂添加量对废旧PU材料回收再利用的影响因素。结果表明，催化剂（KOH）用量为0.9 g时废旧PU的降解效果最好，获得的再生PU硬泡的密度为37.6 kg/cm³，压缩强度为164.2 kPa，热导率为0.015 24 W/（m·K），吸水率为0.429 5 %。