填胶量对BR/SBR/NR发泡材料硫化发泡特性及相结构的影响

采用无转子发泡流变仪系统研究了不同填胶量对顺丁橡胶(BR)/丁苯橡胶(SBR)/天然橡胶(NR)发泡体系的硫化及发泡特性的影响,并采用两步模压法制备了预交联度为30%不同填胶量的发泡材料,通过扫描电镜(SEM)观察并计算出填胶量对相结构(泡孔直径、泡孔壁厚度、单位体积内的泡孔数)的影响。结果表明,体积分数为70%～120%的填胶范围时可呈现典型的硫化历程;填胶体积分数为60%～80%时可清晰地呈现典型的发泡历程;填胶体积分数在70%～90%范围内,随着填胶量增加,泡孔直径显著减小,泡孔壁显著变薄,单位体积内的泡孔数显著增加;填料体积分数在100%～120%范围内对相结构的影响较小。     

发泡剂对丙烯酸酯橡胶发泡材料性能的影响

采用模压法制备丙烯酸酯橡胶(ACM)发泡材料,研究了发泡剂品种和用量对其性能的影响。结果表明:以发泡剂4,4'-氧代双苯磺酰肼(OBSH)或偶氮二甲酰胺(AC)制备ACM发泡材料时,最佳用量分别为ACM用量的6%和7%;以复合发泡剂AC/OBSH、AC/碳酸氢钠、OBSH/碳酸氢钠分别制备ACM发泡材料时,最佳使用量分别为ACM用量的7%、7%、6%;当三组复合发泡剂使用量相同时,复合发泡剂AC/OBSH制备的ACM发泡材料发泡倍率最大,微孔孔径较一致,分散均匀。     

发泡剂对EPDM发泡橡胶性能的影响

采用热空气自由发泡制备EPDM发泡橡胶,研究发泡剂品种和用量对其性能的影响。结果表明,以发泡剂OBSH、AC和H制备EPDM发泡橡胶时,它们的最佳用量分别为10份、15份和10份;当发泡剂用量为10份时,以发泡剂OBSH制备的EPDM发泡橡胶发泡倍率最大。观察发泡橡胶内部结构发现,用发泡剂OBSH制备的EPDM的发泡橡胶内部泡孔结构较均匀、孔径最小。     

发泡剂对软质PVC发泡材料的影响

对发泡剂N，N′-二亚硝基五亚甲基四胺（H）、粗发泡剂（TH）及其与偶氮二甲酰胺（AC）共混物用差示扫描量热仪进行分析以及讨论各种AC共混物对软质PVC发泡材料的影响。当AC／TH／H／稳定剂质量比为4．0／0．8／0．4／6．2时，复合发泡剂受热时分解缓慢、放出热量较小，获得的材料力学性能优异、泡孔均匀细密。     

配方与工艺因素对EPDM模压发泡材料性能的影响

研究了发泡剂Ｈ在ＥＰＤＭ模压发泡材料中的发泡特性、硫化特性以及两之间的匹配关系对发泡效果的影响,同时还考察了配方和工艺因素对发泡体性能的影响。结果表明,为了获得较高的发泡率和良好的发泡质量,应选择硫化诱导期与发泡剂完全分解时间相当的硫化体系;一次硫化的硫化程度决定着胶料出模时的膨胀;二次硫化的发泡材料收缩率较小;高填充时粒径较大的填料对发泡效果的影响较小。     

发泡工艺和发泡剂用量对丁基橡胶发泡材料阻尼吸声性能的影响

研究硫化时间、硫化温度以及偶氮二甲酰胺(AC)发泡剂用量对丁基橡胶发泡材料阻尼性能和吸声性能的影响。结果表明:在165℃下硫化30 min时,发泡丁基橡胶有最佳的阻尼性能;在160℃下硫化50 min时,发泡丁基橡胶有最佳的吸声性能。随着发泡剂AC的加入,丁基橡胶发泡材料的阻尼性能和吸声性能均有明显提升。当发泡剂AC用量较小时,材料阻尼性能较好;当发泡剂AC用量为6份时,材料吸声性能较好。     

发泡剂对人造革发泡倍率与泡孔结构的影响

对比分析了纯放热性发泡剂AC与吸－放热复合发泡剂DDL－105的分解与发泡特性。详细比较了以这两类发泡剂在相同配方和加工条件下样品的发泡倍率、泡孔结构差别以及对温度和时间的依赖关系。     

PC结构发泡制品的注塑工艺研究

探讨了影响注射成型PC结构发泡制品的一些因素,提出了对实际生产有指导作用的建议。     

发泡温度和发泡剂用量对溴化丁基橡胶发泡材料结构与性能的影响

通过无转子发泡流变仪、扫描电镜以及物理机械性能测试等研究了发泡温度和发泡剂4,4’-氧双苯磺酰肼用量对溴化丁基橡胶(BIIR)发泡材料结构与性能的影响。结果表明,随发泡温度或发泡剂用量的提高,BIIR混炼胶的转矩和交联密度均减小,正硫化时间缩短,发泡速率和泡孔内压力明显升高。发泡材料的拉伸强度、撕裂强度等力学性能以及密度均随发泡温度升高而缓慢下降,冲击回弹率则逐渐增大。发泡材料的密度和体积收缩率均随放置时间的延长先逐渐增大,并在第5至第6天时基本不变,但二者增幅都较小,且不同的发泡温度对此变化趋势的影响较弱。当发泡温度为160℃、发泡剂用量为9～12份(质量)时BIIR发泡材料的综合性能较好。     

发泡剂和硫化体系对NR/SBR并用海绵胶性能的影响

探讨发泡剂和硫黄硫化体系对NR/SBR并用海绵胶硫化 发泡特性和物理性能的影响。结果得出,应根据海绵胶的硫化 发泡工艺和物理性能要求选用发泡剂AC和DDL系列;采用发泡剂DDL105,硫化体系的硫黄用量为1～1 2份、促进剂CZ用量为0 5份,海绵胶的硫化与发泡速度匹配性好,拉断强度较高,回弹性较好。     

Mechanical and morphological properties of cellular NR/SBR vulcanizates under thermal and weathering ageing

The effects of addition of two chemical blowing agents in cellular rubber blend of natural rubber (NR) and styrene‐butadiene rubber (SBR) at a fixed blend ratio of 1 : 1 on cure characteristics, and mechanical and morphological properties were invesigated. The chemical blowing agents used in this work were Oxybis (benzene sulfonyl) hydrazide (OBSH) and Azo dicarbonamide (ADC). Three different fillers, fly ash (FA) particles, precipitated silica, carbon black (CB) at their optimum concentrations of 40 phr were used, the FA and silica particles being chemically treated by bis‐(3‐triethoxysilylpropyl) tetrasulphide. The results suggested that the overall cure time decreased with OBSH and ADC contents. The OBSH was more effective in cure‐acceleration of the NR/SBR blend than the ADC. The NR/SBR vulcanized foams produced by OBSH and ADC agents had closed‐cell structures. The specific density and mechanical properties of the blend tended to decrease with increasing blowing agent content. The CB gave NR/SBR foams with smaller cell size, better cell dispersion, and higher mechanical properties than the precipitated silica and FA particles. The heat ageing and weathering resulted in an increase in tensile modulus and hardness, but lowered the tensile strength, ultimate elongation and tear strength. The elastic recovery for cellular NR/SBR vulcanizates with FA was superior to that with CB and silica, the elastic recovery of the blends decreasing with blowing agent content. Resilience property was improved by the presence of gas phases. The optimum concentration of OBSH and ADC to be used for NR/SBR vulcanizates was 4 phr. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Effect of precured degrees on morphology,thermal, and mechanical properties of BR/SBR/NR foams

The ternary composites of 1,4‐cis polybutadiene rubbers (BR), styrene–butadiene rubber (SBR), and natural rubber (NR) foams containing chemical blowing agents Oxybis (benzene sulfonyl) hydrazide (OBSH) were prepared by two‐stage compression molding technique with various precured degrees. Foam force rheometer indicated that the cure rate was match with foaming rate at precured degree of 30%, which the time of the maximum foaming rate was earlier only 14 s than that of the maximum cure rate. SEM presented that the number of cell was denser at precured degree of 30% than those with other precured degrees. The average cell size declined, cell wall thickness became thicker, and cell distribution became narrower just as precured degree was increasing. The results of crosslinking density was measured by equilibrium swelling technique in good agreement with that of magnetism resonance crosslinking density spectrometer measurement, which crosslinking density was increased as precured degrees increased. Differential scanning calorimeter showed that each curve exhibits two steps in heat capacity for BR/SBR/NR foams. With further increase of precured degrees, the two groups of T_gs were all shift to the higher temperature, and the area of the melting peak decreased gradually between −20°C and −40°C. TGA results demonstrated that BR/SBR/NR foams with various precured degrees obtained better thermal stability than those of non‐precured foams. The high density of polymeric foams exhibits the high mechanical properties such as tensile strength, tear strength, and elongation at break. The inflection points of density, cell density, and hardness were all appeared at precured degree of 30%. POLYM. COMPOS., 34:849–859, 2013. © 2013 Society of Plastics Engineers     

Simulation of liquid physical blowing agents for forming rigid urethane foams

A computer‐based simulation for rigid polyurethane foam‐forming reactions was compared with experimental data for six blowing agents including methyl formate and C5‐C6 hydrocarbons. Evaporation of blowing agent was modeled as an overall mass transfer coefficient times the difference in activity of the blowing agent in the gas foam cells versus the resin walls of the cells. Successful modeling hinged upon use of a mass transfer coefficient that decreased to near zero as the foam resin approached its gel point. Modeling on density agreed with experimental measurements. The fitted parameters allowed for interpretations of the final disposition of the blowing agent, especially, if the blowing agent successfully led to larger foam cells versus being entrapped in the resin. The only component‐specific fitted parameters used in the modeling was the activity coefficient that was lower for methyl formate than the value used for hydrocarbons. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42454.     

白炭黑/炭黑并用对NR/BR硫化胶磨耗性能及形态的影响

采用电子显微镜（SEM）研究了白炭黑与炭黑并用对天然橡胶／顺丁橡胶（NR／BR）硫化胶磨耗性能及形态的影响。结果表明：白炭黑和炭黑并用能显著提高硫化胶的耐磨性，当白炭黑／炭黑质量比为45／10时，硫化胶耐磨性最高，其磨耗表面磨纹最细密。     

纳米氧化锌在NR/BR并用胶及SBR胶料中的应用

研究纳米氧化锌替代普通氧化锌在天然橡胶(NR)/顺丁橡胶(BR)并用胶以及丁苯橡胶(SBR)胶料中的应用。结果表明,纳米氧化锌减量10%代替普通氧化锌,NR/BR并用胶及SBR胶料的加工性能和物理性能基本不变,质量减小,成本降低。     

杜仲胶/天然橡胶/顺丁橡胶并用胶的工艺研究

用杜仲胶(TPI)替代部分天然橡胶(NR),并与顺丁橡胶(BR)共混生产出混炼胶,研究了TPI/NR/ BR共混硫化胶料制备过程中,硫化温度、硫化时间、硫化剂的用量、硫化促进剂的种类及用量对胶料物理机械性能的影响。研究结果表明,硫化过程中当硫化温度为150℃、硫化时间为20 min、硫化剂为硫黄(质量不超过3份)和硫化促进剂的含量为2份时,胶料的综合物理机械性能较好。     

Investigation of thermoplastic elastomer (TPE) foaming process using blowing agent by rheological and morphological methods

The effects of a chemical blowing agent (CBA) or an encapsulated physical blowing agent (PBA) on morphological development in ethylene octene copolymer (EOC) matrix using dicumyl peroxide (DCP) as a curing agent were investigated by rheological, mechanical, and morphological methods. Temperature ramp tests were carried out to understand curing and foaming processes. Curing temperature (T_cure) was determined as the crossover temperature where storage modulus G′ coincided with loss modulus G′′ in the rheological point of view. For the CBA, T_cure increased with increasing CBA concentration, whereas for the PBA, T_cure decreased with increasing PBA concentration. Other critical temperatures T_1st, T_2nd by foaming process were determined using the axial normal force. With these critical temperatures (T_cure, T_1st, T_2nd), curing and foaming mechanisms can be estimated. Simultaneously, volume expansions of samples were observed with camera. Morphology and mechanical analysis were conducted on fully cured and foamed ECP (is defined as EOC with DCP) with blowing agent. ECP with the CBA exhibited an irregular open-cell structure, whereas when produced using the PBA, it formed a regular closed-cell structure. Specific tensile strength tended to increase with increasing PBA concentration but as blowing agent concentration increased elongation at break decreased. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47358.     

孔隙度对开孔硅橡胶泡沫材料性能的影响

采用溶析成孔技术制备的硅橡胶泡沫材料,随着成孔剂用量增大,其密度减小,孔隙度提高。根据Ｇｉｂｓｏｎ和Ａｓｈｂｙｓ理论分析,随着孔隙度提高,硅橡胶泡沫材料的拉伸性能降低,而压缩性能变化不大。