慢回弹聚氨酯软泡组合料的制备及应用研究

以慢回弹聚醚、普通聚醚、催化剂、泡沫稳定剂、开孔剂,异氰酸酯等为原料,制备慢回弹聚氨酯聚醚组合料及慢回弹聚氨酯软泡,并检测其性能.结果表明,水用量在2份,L598催化剂在4.5份,模具温度在45℃,异氰酸酯指数在75时,慢回弹聚氨酯软泡具有较好的发泡工艺及泡孔结构,密度与力学性能较好.     

聚氨酯慢回弹块状泡沫的研制

以慢回弹泡沫用聚醚LW-1080和普通软泡聚醚ZS-2802为主原料,制备了聚氨酯慢回弹块状泡沫,讨论了催化剂、硅油、发泡剂、开孔剂及TDI指数对发泡工艺及泡孔结构的影响,并与国内外同类慢回弹聚醚进行了比较.结果表明,复合催化剂胺与锡用量在0.35∶0.06～0.45∶0.10份之间、硅油B-8002的用量在1.0～1.8份之间、发泡剂水的用量在1.5～2.5份之间、开孔剂SK-1900用量在1.5～2.5份之间、TDI指数为80～95时,慢回弹聚氨酯泡沫具有较好的发泡工艺及泡孔结构;LW-1080慢回弹聚醚与国内外同类产品性能相当.     

耐低温慢回弹聚氨酯海绵材料制备及性能研究

以氯铂酸溶液为催化剂,将烯丙氧基聚氧乙烯醚（APEG）和聚甲基氢硅氧烷（PMHS）进行硅氢加成反应合成有机硅改性聚醚（Si-APEG）,并以其作为耐低温剂,制备耐低温慢回弹聚氨酯（PU）海绵。研究了Si-APEG添加量对海绵表观芯密度、开孔率、拉伸性能、硬度、回弹性能以及温湿度敏感指数的影响。结果表明,当Si-APEG添加量为10份时海绵的泡孔结构较理想,综合力学性能最优,回弹性能最低,同时其温湿度敏感指数低至1.01,硬度在-10℃低温下仍可低至53度,因此该添加量下海绵的综合性能最优。     

汽车隔音垫用聚氨酯软质高回弹泡沫的吸音性能研究

通过驻波管法测试不同隔音垫聚氨酯软质高回弹泡沫的吸声系数,结合显微镜对泡沫的力学特性和形态进行观察和分析。研究结果表明,泡沫在低频区的吸声系数随厚度的增加而提高,而在高频区则有所减弱;泡沫的吸声系数随密度增加而提高;泡孔形态对泡沫的吸声性能有显著影响,细密而均一的泡孔有利于声能的吸收;不同异氰酸酯由于反应性和结构上的差异,泡沫也表现出不同的吸声特性;高压发泡生产的泡沫峰值吸声频率稍向高频区移动,复合乙烯–醋酸乙烯共聚弹性体（EVA）后泡沫的峰值吸声频率稍向低频区移动。     

阻燃高回弹聚氨酯泡沫的挥发性研究

使用含氮结构型阻燃聚脲多元醇对阻燃高回弹聚氨酯泡沫的挥发性进行了研究．考察了配方中聚脲多元醇、催化剂、泡沫稳定剂、阻燃剂对泡沫挥发性的影响。研究结果表明,使用聚脲多元醇、反应型催化剂、低挥发性泡沫稳定剂生产的阻燃高回弹聚氨酯软泡较普通阻燃高回弹聚氨酯软泡具有较低的VOC（挥发性有机物）、甲醛释放量和雾化值。     

超细煤粉填充聚氨酯泡沫材料的性能

以聚合MDI和聚醚多元醇为原料,优选发泡剂,加入改性超细煤粉作为填充剂,制备出硬质聚氨酯泡沫材料。通过测试煤粉填充聚氨酯泡沫材料的表观密度、回弹率、压缩强度和氧指数进行分析。结果表明,发泡剂H用量0.1 g时制备的聚氨酯泡沫压缩强度、回弹率较好;加入KH550和KH560改性的超细煤粉,随着煤粉用量增加,聚氨酯泡沫的压缩强度、氧指数得到明显改善。当KH560改性煤粉用量为15份时,聚氨酯性能最优,压缩强度达到0.40MPa,氧指数达到21%,回弹率为5.4%,密度为0.064 g/cm~3。     

泡沫稳定剂在阻燃高回弹聚氨酯泡沫塑料中的应用

分别采用L-5 333,Y-10 366和B-8716三种泡沫稳定剂制备阻燃高回弹泡沫塑料;探讨了泡沫稳定剂对阻燃高回弹聚氨酯（FRHRPU）组合料反应活性、泡孔结构及制品力学性能的影响。结果表明：泡沫稳定剂Y-10 366制备的FRHRPU的拉伸强度为171.18 kPa,撕裂强度为3.23 N/cm和回弹性为58.70%,均高于其他两种硅油的,并且当Y-10 366与多元醇的质量比从0.5/100增加到1.2/100时,制品的泡孔孔径先减小后增大,而制品的开孔率从93%降低到35%。     

高活性高固含量聚合物多元醇的应用

讨论了高活性高固含量聚合物多元醇在普通高回弹箱泡、模塑聚氨酯泡沫生产中的应用。针对箱式发泡、模塑聚氨酯泡沫生产工艺，研究了高活性高固含量聚合物多元醇的发泡配方宽容度，及用量变化对发泡情况及其制品性能的影响，同时与国外产品的发泡及制品性能进行了比较。     

模塑胀气慢回弹聚氨酯泡沫稳定剂的开发

通过对胀气慢回弹发泡市场主要原料聚醚、异氰酸酯的了解,开发了适用于这些原料的泡沫稳定剂WD557。在适当配方体系下,与进口泡沫稳定剂在泡沫制品芯密度、球回弹、透气性、回复时间、泡孔状况等方面进行了比较。结果表明,WD557基本达到了国外产品的水平,可用于胀气慢回弹模塑发泡的生产。     

聚氨酯泡沫开孔剂市场或有新的飞跃

<正>日前,高桥石化用于慢回弹泡沫塑料的聚氨酯泡沫开孔剂试生产取得成功。慢回弹泡沫塑料广泛应用于医疗、家具和舒适休闲产品,具有优异的缓冲、隔音、密封等特殊性能。由于能够满足人们对高舒适性生活的要求,慢回弹聚氨酯泡沫塑料市场未来将可能会产生新的飞跃。慢回弹泡沫塑料是一种特殊的软质泡沫,其发泡过程中必须加入一种     

Cure and mechanical properties of filled SMR L/ENR 25 and SMR L/SBR blends

The effect of blend ratio of natural rubber/epoxidized natural rubber (SMR L/ENR 25) and natural rubber/styrene‐butadiene rubber (SMR L/SBR) blends on scorch time (t₂), cure time (t₉₀), resilience, hardness, and fatigue properties were studied in the presence of carbon black and silica. An accelerated sulfur vulcanization system was used throughout the investigation. The scorch and cure times of the rubber compound were assessed by using a Moving‐Die Rheometer (MDR 2000). Resilience, hardness, and fatigue life were determined by using a Wallace Dunlop Tripsometer, a Wallace Dead Load Hardness Tester, and a Fatigue to Failure Tester, respectively. The results indicate that t₂ and t₉₀ decrease with increasing ENR 25 composition in the SMR L/ENR 25 blend whereas both values increase with increasing SBR content in the SMR L/SBR blend. This observation is attributed to faster cure in ENR 25 and higher saturation in SBR. Resilience decreases with increase in % ENR and % SBR but hardness shows the reverse behavior in their respective blends. The fatigue life increases with % ENR, but it passes through a maximum with % SBR in the respective blends. In all cases, aging lowers the fatigue life, a phenomenon that is caused by the breakdown of crosslinks in the vulcanizate. Differences in all the observed values between carbon black‐filled and silica‐filled blends are associated with the varying degrees of interaction and dispersion of the two fillers in the rubber blend matrix. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 47–52, 2001     

Resilience in Long-Term Viral Infection: Genetic Determinants and Interactions

Virus-induced neurological sequelae resulting from infection by Theiler’s murine encephalomyelitis virus (TMEV) are used for studying human conditions ranging from epileptic seizures to demyelinating disease. Mouse strains are typically considered susceptible or resistant to TMEV infection based on viral persistence and extreme phenotypes, such as demyelination. We have identified a broader spectrum of phenotypic outcomes by infecting strains of the genetically diverse Collaborative Cross (CC) mouse resource. We evaluated the chronic-infection gene expression profiles of hippocampi and thoracic spinal cords for 19 CC strains in relation to phenotypic severity and TMEV persistence. Strains were clustered based on similar phenotypic profiles and TMEV levels at 90 days post-infection, and we categorized distinct TMEV response profiles. The three most common profiles included “resistant” and “susceptible,” as before, as well as a “resilient” TMEV response group which experienced both TMEV persistence and mild neurological phenotypes even at 90 days post-infection. Each profile had a distinct gene expression signature, allowing the identification of pathways and networks specific to each TMEV response group. CC founder haplotypes for genes involved in these pathways/networks revealed candidate response-specific alleles. These alleles demonstrated pleiotropy and epigenetic (miRNA) regulation in long-term TMEV infection, with particular relevance for resilient mouse strains.     

Ultrastrong,elastic, and fatigue-resistant SiC nanowires network

Light, strong, and elastic ceramics are of great interest for widespread engineering applications but it is always been a challenge to design and fabricate such materials for the conflict that lightweight structure usually requires high porosity while high porosity often leads to low strength. Here, we report a lightweight (90.9% porosity) and ultra-strong SiC nanowires network (SiC NN) constructed by highly inter-bonded nanowires in a layered distribution through a facile way. The resulting lamellar SiC NN (L-SiC NN) exhibits a nearly complete compressive resilience from 20% strain while showing significantly high compressive stress (5.7 MPa). In particular, the L-SiC NN shows high storage modulus (12.3 MPa), small damping ratio (0.046), frequency invariant from 20 to 100 Hz, and fatigue resistance up to 100 000 compression-release cycles. In addition, the L-SiC NN possesses high-temperature stability up to 1100°C in air and low thermal conductivity of 0.121 W m^-1 k^-1. These integrated features make the L-SiC NN an attractive substitute for thermal insulators and mechanical energy storage in a harsh environment.     

PTT长丝瞬时拉伸回弹性能研究

在相同条件下对比研究了PET ,PTT和PBT 3种芳香族聚酯长丝的瞬时拉伸回弹性能 ,分析了测定条件对PTT长丝瞬时拉伸回弹性能的影响 ,并初步讨论了 3种芳香族聚酯长丝的瞬时拉伸回弹机理。结果表明 ,PTT长丝的瞬时拉伸回弹性能明显优于PBT长丝 ,更优于PET长丝 ,PTT长丝在低伸长率和高伸长率下均具有优异的瞬时拉伸回弹性能 ;测定PTT长丝瞬时拉伸回弹率时 ,建议采用 0 .5cN/tex的预张力 ,5 0 0mm/min的拉伸速率和 2 0 %的定伸长率等条件     

Effects of the interaction of hardness,resilience, and fatigue properties on the abrasion properties of rubber blends

The establishment of prediction model for abrasion properties of vulcanizates, based on their simple physio‐mechanical properties, is a hot research field in tribology. The hardness (H), resilience (R), and dynamic fatigue fracture parameters (m) of rubber vulcanizates were combined together in this article, named as hardness–resilience product (H^mR), and its relationships with the abrasion loss for various vulcanizates [natural rubber (NR), styrene–butadiene rubber (SBR), butadiene rubber (BR), and their blends] was investigated by using Akron and DIN abrader. The results showed that, for NR/SBR blends with different SBR content, compared with log(H⁴R), the abrasion loss had much better linear relationship with log(H^mR) for both Akron and DIN abrasion. This good linear relationship, for both Akron and DIN abrasion, also appeared in the SBR/BR blends with different BR content. Furthermore, for both blending systems (NR/SBR and SBR/BR), when all the data above were put together, the abrasion loss also had good linear relationships with its log(H^mR) no matter for Akron or DIN abrasion, which indicated that this linear relationship had some universality. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1212‐1219, 2013     

Dynamic-mechanical properties of polybutadiene rubbers

The dynamic properties of high-cis (98%) and cis-trans (42% cis) polybutadienes, crosslinked with 0.1 to 1.0% of crosslinking agent, have been studied using a torsion pendulum method over the temperature range ?170 to +20°C. For the high-cis rubber plots of damping factor (tan δ) against temperature showed the expected peak in the glass-transition region with an additional peak in the neighbourhood of 0°C attributable to crystallization. The cis-trans rubber showed two damping maxima in the transition region, separated by 30 to 40°C (depending on the degree of crosslinking), suggesting incipient phase separation of the component structures. The rebound resilience of the high-cis rubber at room temperature exceeded that of the cis-trans, reaching 92% at the highest crosslink density. Plots of resilience versus temperature for both rubbers showed a single minimum in the glass transition region.     

Micelle Crosslinked Polyacrylic Acid Hydrogels with Resilience and Self-Recovery Properties

Micelle crosslinking method is one of the several techniques to fabricate hydrogels with good mechanical performance. Micelle crosslinked hydrogels reported so far are fabricated using a multistep preparation process due to the functionalization of block copolymers or surfactants with acrylate, aldehyde, azo, or reversible addition-fragmentation chain transfer groups to create a polymer network. Herein, a simple one-step approach is introduced to produce resilient hydrogels prepared by bulk polymerization of acrylic acid and esterification with Triton X-100 (TX-100) in the presence of catalyst sulfuric acid (H₂SO₄). The advantage of this study is that TX-100 surfactants self-assembling into micelles are directly bonded onto polymer chains through an ester bond without any further modification. The obtained hydrogels exhibit tensile strengths up to 135 ± 8 kPa and compressive strengths up to 16 ± 1 MPa over 94% strains as well as complete self-recovery and high resilience abilities (≈86% at strains up to 400%) originating from hydrophobic associations in the core of micelles acting as dynamic cross-linkers along with hydrogen bonds and entanglements between polymer chains acting as additional crosslink points. The overall results show that the hydrogels can be good candidate as elastic materials in many fields.     

Influence of stretching on the resilience of LLDPE monofilaments for application in artificial turf

Polymeric filaments have been used successfully in artificial turf, however lack of resilience and excessive fibrillation are still the main problems encountered on artificial turf fields and especially when used for football. Resilience is the ability to recover rapidly from a deformation, especially from a bending deformation. FIFA and EN standards recognize the 0.8 m‐Lisport for predicting filament behavior, but this method does not provide any information concerning the resilience of individual filaments. Furthermore, it is merely a qualitative method that only assesses the system in its entirety. The research presented in this article is twofold, first to develop a test method to assess the resilience of a single filament and to correlate with the established methodology, dynamic bending by Favimat R. Second to characterize fiber morphology and to correlate the morphology characteristics with the resilience measurements. A good correlation of the static bending with dynamic bending is obtained and both test methods provide valuable information about the influence of the processing parameters on the resilience. Dynamic scanning calorimetry, Raman and WAXS measurements clearly prove the influence of the structure and more specifically of the amorphous phase on the resilience. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and characterization of composites of polyaniline and polyurethane‐modified epoxy

A toughened, semiconductive polyaniline/polyurethane (PANI/PU)‐epoxy nanocomposite was prepared using a conductive polymer, PANI, and a PU prepolymer‐modified diglycidyl ether of bisphenol A (DGEBA) epoxy. The formation of a nanostructure was confirmed by Fourier transform infrared spectroscopy and SEM. The mechanical properties of the composites were evaluated and compared with those of the corresponding matrix. The improvement in impact strength of the composites (especially in the PANI/PU(PPG2000)‐epoxy system) was explained after fracture surface analysis using SEM. DSC and TGA studies indicated that the thermal properties of these composites were comparable to those of DGEBA epoxy. A conductivity in the range 10^?9–10^?3 S cm^?1 was obtained, depending on the testing frequency (10³–10⁷ Hz) and the PANI content incorporated. Copyright © 2006 Society of Chemical Industry     

高回弹块状泡沫塑料的试制

以自产聚醚多元醇为主要原料,试制成高回弹块状聚氨酯软泡。讨论了聚合物多元醇和水用量、低不饱和度聚醚等因素对泡沫性能的影响。