微孔注塑发泡聚氨酯成型工艺及微观结构研究

采用超临界CO_2微孔注塑成型工艺制备热塑性聚氨酯弹性体(TPU)微孔泡沫材料,研究超临界流体(SCF)注塑发泡工艺对TPU泡沫微观结构及力学性能的影响规律。本文基于正交优化实验设计,以制品拉伸强度为优化指标,优化微孔成型工艺参数。最优微孔注塑工艺为:注射量16 cm~3;SCF含量0.4%;注射速度60 cm~3/s;保压压力1 MPa。本文通过研究成型工艺对制品结构及力学性能的影响,为超临界CO_2制备高发泡率高性能TPU软质泡沫材料提供技术支持。     

聚醚酰亚胺均相成核发泡行为研究

以超临界CO₂为发泡剂,采用间歇式发泡技术制备了聚醚酰亚胺（PEI）微孔泡沫。通过改变发泡温度、发泡压力与样品浸泡时间等工艺条件,研究了PEI的均相成核发泡行为。实验还通过二次降压法制备了具有复合泡孔结构的PEI微孔泡沫材料。结果表明,复合泡孔结构提高了PEI微孔泡沫的发泡倍率,第一次压力降ΔP₁与第二次保压时间Δt₂是影响复合泡孔结构参数的重要影响因素。     

聚醚酰亚胺发泡技术研究进展

介绍了高性能热塑性聚合物泡沫——聚醚酰亚胺（PEI）泡沫的间歇式发泡、挤出发泡、注射成型发泡等制备技术,论述了发泡剂与成核剂的选用对PEI泡沫性能的影响,对近年来国内外PEI发泡技术（制备技术、发泡剂与成核剂的选用）的研究进展进行了详细综述,并对PEI泡沫的未来发展进行了展望。     

热塑性聚醚砜、聚醚酰亚胺泡沫材料的制备与研究现状

介绍了高性能聚合物泡沫聚醚砜（PES）和聚醚酰亚胺（PEI）的制备工艺;综述了制备工艺、加工条件、纳米填料、共混等对于泡孔结构与泡沫性能的影响;并列举了PES和PEI泡沫的应用和发泡行为的异同。     

聚醚砜超临界CO2发泡行为研究

以超临界CO₂为发泡剂,采用间歇发泡法制备了聚醚砜（PES）泡沫。采用旋转流变仪和扫描电子显微镜分析表征了PES发泡的均相成核行为,继而分别以滑石粉和二氧化硅（SiO₂）作为异相成核剂,探究了PES发泡过程中的异相成核行为。结果表明,间歇发泡法制备PES泡沫的发泡区间为200~230 ℃;最佳浸泡压力为20 MPa;最佳浸泡时间为3 h;未改性PES的泡孔直径均可在10 μm以下,泡孔密度在10⁹~10¹⁰ 个/cm³之间,但泡孔壁较厚;SiO₂相对于Talc,表现出更显著的异相成核作用;在210 ℃、3 h、20 MPa的发泡条件下,添加0.9 %（质量分数,下同）的SiO₂,可得到泡孔直径为0.77 μm,泡孔密度为7.14×10¹¹ 个/cm³的PES微孔泡沫。     

高分子材料成型加工装备及技术的进展、趋势与对策(下)

高分子合成工业取得的很大进展、汽车等工业的发展以及可持续发展的社会问题等在推动高分子材料成型加工装备及技术的发展,开发了各种先进技术与装备.本文从成型原理、装备、优缺点和应用等方面,介绍和分析其中的一些主要技术,包括超临界流体辅助微孔发泡技术（挤出与注塑）、流体（气体、水）辅助注塑技术、复杂制品的吹塑和注塑技术、聚合物共混和纳米复合加工成型技术、高阻渗性制品成型技术以及全电动注塑机和吹塑机.     

高分子材料成型加工装备及技术的进展、趋势与对策(上)

高分子合成工业取得的很大进展、汽车等工业的发展以及可持续发展的社会问题等在推动高分子材料成型加工装备及技术的发展,开发了各种先进技术与装备.本文从成型原理、装备、优缺点和应用等方面,介绍和分析其中的一些主要技术,包括超临界流体辅助微孔发泡技术（挤出与注塑）、流体（气体、水）辅助注塑技术、复杂制品的吹塑和注塑技术、聚合物共混和纳米复合加工成型技术、高阻渗性制品成型技术以及全电动注塑机和吹塑机.     

专利

<正>一种超临界CO_2发泡制备聚醚砜酮-成核剂复合材料的方法公开号:CN103382261A公开日:2013-11-06申请人:大连工业大学摘要本发明公布了一种超临界CO_2作为发泡剂制备聚醚砜酮-成核剂微孔发泡体系的方法,该制备方法步骤如下:将充分干燥的聚醚砜酮、成核剂粉末混合均匀置于模具中,在马弗炉内烧结使物料熔融,固化后裁切成样条。将模压成型的样条置于充满超临界CO_2气氛的高压釜中,使流体渗透进样条中直至饱和,将样条迅速取出,置于高温环境中发泡,经冷却、清洗、干燥,得到泡孔尺寸小、泡孔密度大、泡孔分布均匀的聚醚砜酮-成核剂发泡材料。此种方法制备的聚醚砜酮-成核剂微孔发     

超临界工艺制备聚乳酸泡沫技术研究

超临界流体(SCF)是一种制备可降解聚合物泡沫的先进技术。利用超临界二氧化碳发泡成形技术,制备可降解高分子聚乳酸(PLA)泡沫材料,并通过条件试验确定了最适合的成形工艺参数,同时结合聚乳酸材料的物理性质,对控制泡沫形态的机理进行了研究。     

特种工程塑料泡沫研究进展

特种工程塑料具有高强度、高模量、耐高温等优异的综合性能,但该类材料的加工温度过高,导致其基本无法采用传统的发泡工艺对其进行发泡,而超临界流体发泡技术为制备特种工程塑料泡沫提供了可能。首先,对超临界流体发泡技术的原理、成型方式以及发展现状进行了介绍,然后综述了超临界流体发泡技术在制备特种工程塑料泡沫方面的研究进展,其中,重点阐述了几种典型的聚芳醚类特种工程塑料微孔泡沫的制备,泡孔结构的调控方法及其性能的研究。最后,对特种工程塑料泡沫的发展现状进行了总结,并有针对性地提出了目前特种工程塑料发泡方法在材料设计、设备研发、过程控制方面亟待解决的问题。     

酚醛-三聚氰胺聚合物改性聚醚多元醇用于聚氨酯硬泡的性能研究

用酚醛-三聚氰胺聚合物改性的聚醚多元醇(PFMP-Polyol)制备硬质聚氨酯泡沫,考察了PFMP-Polyol的用量对泡沫的发泡性能、物理机械性能的影响。结果表明,在HCFC-141b发泡体系中,PFMP-Polyol的加入可提高发泡反应速度,使泡沫泡孔细腻、均匀,泡沫的压缩强度、尺寸稳定性均有明显的提高;用于环戊烷发泡体系中,当PFMP-Polyol的质量分数占聚醚多元醇的30%、模压泡密度在34.2 kg/m~3,压缩强度(水平方向)为254.2 kP,导热系数可降低至20.8 mW/(m·K)。     

聚合物微发泡材料制备技术理论研究进展

20世纪90年代末,超临界流体(SCF)制备聚合物微发泡材料实现了工业化,这种方法制备的微发泡材料具有非常多的优点,被誉为"21世纪的新型材料"。介绍了SCF的概念、性质以及其在相关领域的应用情况。然后对聚合物微发泡材料的理论研究进展进行了介绍,主要回顾了3个方面的研究内容,包括气体在聚合物中的溶解行为、泡孔的形成和长大机理以及聚合物/气体体系的流变行为等。这些基础性的研究工作对于深入理解聚合物微发泡材料的形成机理及后续的应用研究具有非常重要的意义。     

难燃聚氨酯软质泡沫的制备及性能研究

用新型难燃接枝聚合物聚醚多元醇和聚醚多元醇3050的混合物与甲苯二异氰酸酯(TDI)自由发泡反应，制备了阻燃型聚氨酯软质泡沫。讨论了难燃接枝聚合物聚醚多元醇的用量对聚氨酯软质泡沫密度、氧指数和力学性能的影响。结果表明，随着难燃聚醚用量的增加，聚氨酯软质泡沫的阻燃性能提高，力学性能也有显著提高，泡沫体的密度降低。     

Natural Palm Olein Polyol as a Replacement for Polyether Polyols in Viscoelastic Polyurethane Foam

The impact of replacing three polyether polyols with different levels of a single palm olein‐based natural oil polyol (NOP) was systematically correlated with the changes in foaming reactivity, cell structure, physico‐mechanical properties, and morphology of viscoelastic (VE) foams. The data show that replacing the polyether polyols with the NOP slightly increased the rate of the foaming reactivity. Increasing the NOP content resulted in increased cell size and cells remained fully open. Increased NOP content contributed to higher load bearing properties of VE foam, which can be attributed to higher functionality of NOP compared to polyether polyols. Addition of the NOP slightly increased the resilience of the foams, however, the hysteresis which is the measure of energy absorption remained mostly unaffected. Age properties, characterized by dry and humid compression sets, were mostly unaffected by the replacement of the polyether polyol with the NOP. The addition of NOP did not impact the morphology of the VE foam polymer matrix, which appears to retain a low degree of hard and soft segment domain separation. Overall, the results demonstrate a feasibility that the NOP can be used to partially replace the polyether polyols in VE polyurethane foams without significant impact on the functional performance.     

Microwave-assisted rapid fabrication of robust polyetherimide bead foam parts

Polyetherimide (PEI) is an important candidate for fabrication of high-performance polymer foams. Nevertheless, the manufacture of PEI foamed parts with specific three-dimensional geometry shape and lightweight properties remains a big challenge worldwide. Herein, a microwave (MW)-assisted foaming and selective sintering approach was proposed towards rapid fabrication of robust PEI bead foams. During the process, compressed carbon dioxide/tetrahydrofuran was used as physical co-foaming agent, and the surface-coated graphene nanoplatelets (GNPs) was used as MW absorbent. Upon MW irradiation, the GNPs selectively heated and served as solders that effectively facilitated the foaming of expandable PEI (EPEI) beads, and strongly promoted the local polymer melt and entanglement across the surface of EPEI beads. The MW irradiation power and time were considered as the important parameters to achieve fine inter-bead bonding strength between foamed beads. As a model system, we successfully fabricated a 25-mm-thickness foamed part with an apparent density of 0.32 g/cm³ and achieved excellent inter-bead bonding performance. Specifically, we also utilized the COMSOL Multiphysics simulations to study the MW selective heating mechanism. This MW-assisted fabrication strategy offers a new foaming approach toward high-performance polymer foamed parts for many advanced applications.     

Paclitaxel release from micro-porous PLGA disks

Micro-porous biodegradable polymeric foams have potential applications in tissue engineering and drug delivery systems. A two-stage fabrication process combining spray drying and supercritical gas foaming is presented for the encapsulation of paclitaxel in micro-porous PLGA (poly lactic glycolic acid) foams. Encapsulation of paclitaxel in the PLGA polymer matrix was achieved and these foams have potential application as a new type of surgical implant for controlled release of paclitaxel. This technique may also be applied to other hydrophobic drugs which face problems of slow release when encapsulated in a compact polymeric device. The micro-porous structure helps to increase drug release rate due to a shorter diffusion path of the drug in the polymer. The final residual organic solvent content in the polymer was low and well within safety limits due to the high miscibility of supercritical CO₂ with the organic solvent. The pore size distribution, the phase behavior, and the in vitro swelling behavior of the foams were characterized. In vitro release results showed a nearly constant release rate for up to 8 weeks. The release profiles from micro-porous foam and from compressed disks were compared to assess the performance of micro-porous foams as sustained release implants. The foams implanted intracranially in mice showed therapeutic concentrations of paclitaxel at distant regions of the brain even after 28 days of implantation.     

高活性自催化聚醚多元醇的应用研究

将高活性自催化聚醚多元醇应用于高回弹泡沫中,通过发泡实验确定了其自催化活性及与胺类催化剂配合使用时的最佳配比;该聚醚多元醇用于TM体系也可起到催化作用。同时,与用普通聚醚多元醇制得的泡沫相比,用该聚醚多元醇制得的泡沫VOC值明显降低。