HIPS/CG-ATH纳米复合材料的性能

采用熔融共混法制备出了高抗冲聚苯乙烯(HIPS)/高性能纳米氢氧化铝(纳米CG-ATH)复合材料,研究了高性能纳米氢氧化铝的加入量对高抗冲聚苯乙烯阻燃性能、力学性能和热稳定性的影响.结果表明,高性能纳米氢氧化铝的加入有助于提高高抗冲聚苯乙烯的极限氧指数、拉伸强度、弯曲模量和热稳定性,但对高抗冲聚苯乙烯的冲击强度会产生不...     

高抗冲聚苯乙烯的无卤阻燃

采用熔融共混法制备出了高抗冲聚苯乙烯(HIPS)/高性能纳米氢氧化铝(nano-CG-ATH)/包覆红磷(ERP)/改性聚苯醚(MPPO)无卤阻燃复合材料,研究了nano-CG-ATH、ERP和MPPO对HIPS基复合材料阻燃性能、力学性能和热稳定性的影响;利用扫描电镜分析了HIPS基复合材料燃烧后的炭层形貌;利用傅里叶变换红外光谱分析了HIPS/nano-CGATH/ERP/MPPO(60/6/9/25)复合材料及其经不同温度热处理后残留物的结构。结果表明,nano-CG-ATH、ERP和MPPO之间有很好的协效阻燃效果,当nano-CG-ATH用量为6%(质量分数,下同),ERP用量为9%,MPPO用量为25%时,HIPS复合材料的极限氧指数达到27.5%,UL-94级别达到V-0级;该复合材料的拉伸强度达到30.04 MPa,弯曲模量达到2485.60 MPa;热分解后残留物质的量达到10.58%。但是该复合材料的冲击性能有待提高。     

SEBS-g-MAH对PPO/HIPS/滑石粉复合体系形态及力学性能的影响

采用扫描电镜、力学和流变测试等手段研究了苯乙烯-乙烯/丁烯-苯乙烯嵌段共聚物接枝马来酸酐(SEBS-g-MAH)对聚苯醚(PPO)/高抗冲聚苯乙烯(HIPS)/滑石粉复合体系相容性和力学性能的影响。结果表明,滑石粉的加入使复合体系的拉伸强度略有降低,断裂伸长率和冲击性能降低较严重;SEBS-g-MAH能起到界面增容作用,有利于填料的分散和增强界面相互作用,提高了复合体系的韧性。文中进一步讨论了SEBS-g-MAH的加入对复合体系加工流变行为的影响,结果表明,SEBS-g-MAH的加入提高了复合体系在低剪切速率下的表观黏度,使材料剪切敏感性增加。     

阻燃型HIPS基材料的制备及阻燃机理研究

利用熔融共混法制备高抗冲聚苯乙烯(HIPS)/包覆红磷(ERP)/高性能纳米氢氧化铝(纳米CG-ATH)材料,研究了ERP、纳米CG-ATH对HIPS基材料机械性能、热稳定性和燃烧性能的影响情况;通过扫描电子显微镜(SEM)观察了HIPS基材料经过燃烧之后的炭层情况;利用傅里叶变换红外光谱(FT-IR)研究了HIPS/纳米CG-ATH/ERP[三者含量分别为68%/20%/12%(wt,质量分数,下同)]复合材料及其在不同温度下热处理过的残留物结构。结果表明:ERP和纳米CG-ATH间的协同阻燃效果很好,当ERP为12%、纳米CG-ATH为20%时,HIPS基材料的UL-94垂直燃烧级别达V-0,极限氧指数(LOI)达到27%;该材料的热稳定性、弯曲性能和拉伸性能均较好,但冲击性能需要进一步提高。     

HIPS/SMA/CG-ATH纳米复合材料性能研究

采用熔融共混法制备出了高抗冲聚苯乙烯(HIPS)/苯乙烯接枝马来酸酐(SMA)/CG-ATH纳米复合材料,研究了SMA的加入量对复合材料阻燃性能、力学性能和界面粘结性能的影响.结果表明,SMA的加入可以提高复合材料的阻燃性能、拉伸性能和弯曲性能,但对复合材料冲击性能的提高没有产生明显的效果;SMA的加入有助于强化纳米CG-ATH在HIPS基体中的分散性及其与HIPS基体间的界面粘结性.     

不同冲击断裂方式下橡胶粒子形态对HIPS脆韧转变的影响

核-壳型/蜂窝型高抗冲聚苯乙烯(HIPS)树脂在Izod冲击和落锤冲击断裂过程中的脆-韧转变行为不同。透射电镜(TEM)对亚断裂形变区的观察表明,蜂窝型HIPS对落锤冲击作用下的脆韧转变敏感,应力集中能有效引发基体的塑性形变,呈韧性断裂,但在v-notched Izod冲击断裂过程中,却呈脆性;而核-壳型HIPS的冲击断裂性能与之相反。将LDO假说引入冲击破坏研究并结合损伤竞争准数Da和Vincent图探讨了分散相特性及冲击方式对脆韧转变行为的影响。     

无卤阻燃高抗冲聚苯乙烯及其增韧研究

以可膨胀石墨(EG)和微胶囊红磷(MRP)为无卤阻燃剂对高抗冲聚苯乙烯(HIPS)进行阻燃改性,通过熔融共混法制备了一系列不同组成的HIPS/EG/MRP复合材料。采用氧指数、水平燃烧和垂直燃烧方法研究了复合材料的阻燃性能,研究表明,在阻燃剂用量相同时,与单独加入EG和MRP相比,同时加入EG和MRP所制备的HIPS复合材料的阻燃性能更好,当HIPS/EG/MRP的质量比为70/20/10时,HIPS复合材料的阻燃性能最佳,氧指数可达27.4%,水平燃烧性能和垂直燃烧性能分别达到FH-1级和FV-0级。在最佳阻燃剂配比下,研究了苯乙烯-丁二烯-苯乙烯共聚物(SBS)对HIPS复合材料的阻燃性能和力学性能的影响,结果表明,SBS的加入能够有效的改善HIPS复合材料的力学性能,且几乎不影响其阻燃性能。     

HIPS/PPO/PS/PB-g-PS共混物的力学性能与形态结构

采用乳液接枝聚合技术在粒径300nm的聚丁二烯(PB)乳胶粒子上接枝苯乙烯(St),制备了核壳比(PB与PS的质量比)为70/30的PB-g-PS接枝共聚物。将其与高抗冲聚苯乙烯(HIPS)、聚苯醚(PPO)和聚苯乙烯(PS)树脂进行熔融共混制得了一系列HIPS/PPO/PS/PB-g-PS共混物,研究了PPO/PS的组成对共混物力学性能和形态结构的影响。结果发现,在HIPS/PPO/PS共混体系中引入PB-g-PS后,HIPS中的大粒径橡胶粒子(2μm~4μm)和PB-g-PS小粒径橡胶粒子(300 nm)具有良好的协同增韧作用;随着基体中PPO含量的增加,共混物的冲击强度、拉伸强度和断裂伸长率均呈上升趋势;当PPO/PS质量比在25/75~50/50范围内3时,共混物冲击强度出现突变式增大,由300 J/m提高至600 J/m。形态结构研究结果表明,随着基体中PPO含量增加,PB-g-PS弹性体粒子在基体中的分散程度获得明显改善;当PPO质量分数低于10%时,主要为银纹屈服形变;当PPO质量分数高于20%时,主要为剪切屈服形变。     

玻璃纤维增强HIPS制备阻燃建筑模板材料研究

制备了阻燃型短玻纤增强高抗冲聚苯乙烯(HIPS)复合材料,研究了经KH-570(γ-甲基丙烯酰氧丙基三甲氧基硅烷)偶联剂处理的玻纤用量对复合材料拉伸性能、冲击性能、弯曲性能、热性能及加工性能的影响,以及溴系阻燃剂十溴二苯乙烷(DBDPE)和三氧化二锑的协同阻燃作用。最后用扫描电镜观察复合材料的微观形态。结果表明,红外光谱表征证明了KH-570有效地与玻纤表面结合;玻纤可显著地提高HIPS力学性能,玻纤用量30%时,综合性能最优,并使HIPS维卡软化点提高到107℃以上;DBDPE并用三氧化二锑协同阻燃,可使HIPS的氧指数由17.8%提高到24.8%;KH-570偶联剂能有效地改善其界面,其破坏为混合破坏。     

镍化合物对HIPS基PLS复合材料阻燃性能的影响

以高抗冲聚苯乙烯(HIPS)为基体材料,采用锥形量热仪(CONE)实验研究了碱式碳酸镍、硫酸镍、氯化镍、氧化镍四种镍化合物对HIPS阻燃性能及硫酸镍和氧化镍对HIPS/蒙脱土(OMMT)复合材料阻燃性能的影响。采用扫描电镜(SEM)等技术研究了复合材料燃烧残余物的结构。CONE结果表明,单独加入硫酸镍和氧化镍后均可显著降低纯HIPS的热释放速率,氧化镍与OMMT复配可进一步提高材料的阻燃性能。对复合材料燃烧残余物的结构分析表明,氧化镍能与OMMT发生较强的相互作用,形成的炭层更加致密。     

微胶囊红磷和聚苯醚对高抗冲聚苯乙烯的协同阻燃作用

利用微胶囊红磷(MRP)和聚苯醚(PPO)来提高高抗冲聚苯乙烯(HIPS)的阻燃性能, 通过熔融共混法制备了一系列不同组成的MRP-PPO/HIPS复合材料。采用水平燃烧、垂直燃烧、氧指数、锥形量热分析、高温热分解实验等方法研究了复合材料的阻燃性能。研究表明, 阻燃剂用量相同时, 在HIPS基体中同时加入MRP和PPO得到的复合材料比单独加入MRP或PPO得到的复合材料具有更好的阻燃性能。当MRP-PPO/HIPS的质量比为10:20:70时, 复合材料的氧指数为23.9%, 水平燃烧级别达到FH-1级, 垂直燃烧级别达到FV-0级, 阻燃性能达到最佳。MRP用量过多时, 复合材料的阻燃性能下降。研究认为, PPO和MRP对HIPS具有较强的协同阻燃作用。两者以适当比例并用时能够使复合材料在燃烧时的热释放速率和燃烧热大幅度减小, 降低了气相燃烧区的温度, 起到气相阻燃作用。同时, 复合材料在热分解和燃烧时能够生成连续和致密的炭层, 抑制了燃烧过程中的热量传递和物质交换, 起到凝聚相阻燃作用。因此, 复合材料的阻燃性能显著改善。     

Dynamic mechanical spectroscopy applied to study the thermal and photodegradation of poly(2,6-dimethyl-1,4-phenylene oxide)/high impact polystyrene blends

The thermal and photooxidative degradation of high impact polystyrene (HIPS) and its blends with poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) have been studied under accelerated conditions. HIPS and its blends containing 40, 50 and 60% of PPO, called PPO 40, PPO 50 and PPO 60, were submitted to thermal (ASTM-D5510) and photochemical (ASTM-G53) ageing. The extent of degradation was accompanied by infrared spectroscopy (FTIR), Raman spectroscopy (FT-Raman) and dynamic mechanical analysis (DMA). FTIR and DMA are techniques very sensitive to chemical groups and to relaxation of polymers, respectively. DMA showed that the glass transition of the polybutadiene phase of the external layers of aged HIPS and its blends is shifted to higher temperatures in comparison to non-aged reference samples. The deeper the analysed layer, the more the T_g is shifted to the T_g of the reference material. By FTIR analysis, it was possible to register spectroscopic changes only in the outermost layer (80 μm) while, by DMA, it was possible to detect changes at least to 800 μm depths. The FT-Raman showed that the cis units are the first to be degraded, which explains the shift of the T_g of the polybutadiene phase.     

Rubber-toughening of plastics

The effects of stress-and strain-history upon the mechanical properties of HIPS (highimpact polystyrene) and of blends containing HIPS and PPO^R resin have been studied in a number of different tests, including repeated creep testing of individual specimens and repeated tensile tests at constant strain-rate upon individual specimens. The results show that craze formation increases volume and lowers Young's modulus in specimens subjected to tensile strain, and that strained specimens recover only slowly towards the properties of the unstrained material. Recovery is accelerated by heating, or by immersion in alcohols. A given initial strain produces a greater reduction in modulus in HIPS, which deforms almost entirely by crazing, than in HIPS/PPO blends, which deform by a combination of crazing and shear band formation. The properties of strained specimens are dominated by the distinctive non-linear mechanical behaviour of crazes, and the problems of constructing models to represent this behaviour are discussed.     

高抗冲聚苯乙烯的断裂韧性

综述了高抗冲聚苯乙烯断裂韧性方面工作的进展。评述了高聚物的脆性断裂－韧性断裂转变、分散相粒子大小及其分布、基材与分散相间的界面粘结等因素对高抗冲聚苯乙烯冲击韧性的影响。     

TMC-300对PLLA/PPC合金性能的影响

为了改善聚L-乳酸(PLLA)/聚碳酸亚丙酯(PPC)合金的结晶等性能,利用熔融共混法在合金中添加PLLA专用酰肼类成核剂TMC-300。采用差示扫描量热仪(DSC)、广角X射线衍射仪(WAXD)、小角X射线散射仪(SAXS)、偏光显微镜(POM)、扫描电子显微镜(SEM)及力学分析方法考察了PLLA专用酰肼类成核剂TMC-300对PLLA/PPC合金的结晶及力学性能的影响。结果显示,添加质量分数为0.5%的TMC-300对PLLA/PPC合金之间的相容性影响甚微,但可提高PLLA/PPC合金的结晶度,使合金中PLLA的长周期减小,且添加TMC-300的合金中PLLA晶核数目增多,球晶尺寸减小。此外,添加0.5%的TMC-300可提高PLLA/PPC合金整体的断裂伸长率。在质量比为80/20的PLLA/PPC合金中加入0.5%的TMC-300后,该三元共混材料的冲击韧性达到最佳。     

Influences of processing parameters and heat treatment on microstructure and mechanical behavior of Ti-6Al-4V fabricated using selective laser melting

Selective laser melting (SLM) has provided an alternative to the conventional fabrication techniques for Ti-6Al-4V alloy parts because of its flexibility and ease in creating complex features. Therefore, this study investigated the effects of the process parameters and heat treatment on the microstructure and mechanical properties of Ti-6Al-4V fabricated using SLM. The influences of various process parameters on the relative density, tensile properties, impact toughness, and hardness of Ti-6Al-4V alloy parts were studied. By employing parameter optimization, a high-density high-strength Ti-6Al-4V alloy was fabricated by SLM. A relative density of 99.45%, a tensile strength of 1 188 MPa, and an elongation to failure of 9.5% were achieved for the SLM-fabricated Ti-6Al-4V alloy with optimized parameters. The effects of annealing and solution aging heat treatment on the mechanical properties, phase composition, and microstructure of the SLM-fabricated Ti-6Al-4V alloy were also studied. The ductility of the heat-treated Ti-6Al-4V alloy was improved. By applying a heat treatment at 850 ℃ for 2 h, followed by furnace cooling, the elongation to failure and impact toughness were found to be increased from 9.5% to 12.5%, and from 24.13 J/cm² to 47.51 J/cm², respectively.The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-022-00389-y     

聚苯醚改性环氧树脂基覆铜板的研制

利用浊点绘制了聚苯醚与溴化环氧树脂体系的相图,通过对相图的分析研究了体系的相容性;讨论了胶液的均一性、借助凝胶时间的测定研究了固化剂双氰胺以及促进剂2-乙基-4-甲基咪唑对体系反应性的影响;分析讨论了含胶量对体系电性能、机械性能以及耐水性的影响,确定了合理的制作半固化片的工艺。通过研究认为,聚苯醚/溴化环氧树脂体系表现最高临界相容温度行为,同时当聚苯醚含量为60%~70%时体系的浊点曲线与玻璃化转变温度曲线相交;聚苯醚/溴化环氧树脂体系在甲苯-二氯甲烷的混合溶剂中的均一性良好,得到的层压板的性能较优,比传统的FR-4型覆铜板的性能尤其是电性能、耐热性、弯曲强度以及耐水性提高幅度较大。     

铸造铝铜合金的冲击韧性

研究了铝铜系铸造合金的冲击韧性与显微结构和拉伸性能之间的关系 .结果表明 ,显微结构对冲击韧性和拉伸性能有着相似的影响规律 ,即晶粒尺寸越小 ,冲击韧性值越大 .在本文实验条件下 ,当强度比 (σ0 .2 /σb)小于 0 .5 5 ,延伸率大于 1 5 %时 ,合金表现出高的冲击韧性 .     

钛酸酯偶联剂改性磷石膏及其在PC/ABS中的应用

以钛酸酯偶联剂(101、201、311)改性磷石膏,测试改性磷石膏的表面吸油值和接触角,讨论不同结构钛酸酯偶联剂对磷石膏的改性效果。采用熔融挤出法制备钛酸酯改性磷石膏/PC/ABS合金,分析不同结构钛酸酯改性磷石膏对PC/ABS的力学影响。研究表明,3种钛酸酯偶联剂均能降低磷石膏表面亲水性,其中(201)偶联剂改性效果最好,其最佳改性条件:(201)偶联剂加入量为2%,反应温度为40℃。改性磷石膏作为填料填充PC/ABS,可以不同程度地提升合金体系力学性能,其中(201)改性磷石膏对改善合金体系的拉伸强度、弯曲强度效果显著,分别为45.71MPa、141.48MPa,分别比PC/ABS提高了10.04%、29.13%;冲击韧性为12.57kJ/m^2,提高了38.13%。(311)改性磷石膏填充PC/ABS合金体系时,将体系冲击韧性提高了77.91%。扫描电镜表征结果显示,改性磷石膏嵌入了PC/ABS孔洞间,其中(201)改性磷石膏分散较好。     

Morphologies and physical properties of PA1010/HIPS/HIPS-g-MA ternary blends

The effect of the content of a copolymer consisting of high impact polystyrene grafted with maleic anhydride (HIPS-g-MA) on morphological and mechanical properties of PA1010/HIPS blends has been studied. Blend morphologies were controlled by adding HIPS-g-MA during melt processing, thus the dispersion of the HIPS phase and interfacial adhesion between the domains and matrices in these blends were changed obviously. The weight fractions of HIPS-g-MA in the blends increased from 2.5 to 20, then much finer dispersions of discrete HIPS phase with average domain sizes decreased from 6.1 to 0.1 m were obtained. It was found that a compatibilizer, a graft copolymer of HIPS-g-MA and PA1010 was synthesized in situ during the melt mixing of the blends. The mechanical properties of compatibilized blends were obviously better than those of uncompatibilized PA1010/HIPS blends. These behaviors could be attributed to the chemical interactions between the two components of PA1010 and HIPS-g-MA and good dispersion in PA1010/HIPS/HIPS-g-MA blends. Evidence of reactions in the blends was seen in the morphology and mechanical behaviour of the solid. The blend containing 5 wt% HIPS-g-MA component exhibited outstanding toughness.