HDPE/PA6共混阻隔材料的制备及研究

采用熔融挤出法制备了高密度聚乙烯(HDPE)与马来酸酐(MAH)的接枝物(HDPE-g-MAH),并用红外光谱证实了接枝反应。以此接枝物为相容剂制备HDPE/PA6共混材料。研究了PA6和相容剂用量对共混材料形态结构、力学性能及阻气性能的影响。SEM表明相容剂可以明显改善HDPE与PA6的相容性。PA6的加入显著提高了HDPE对氧气的阻隔性能。     

Influence of reactive compatibilizers on the rheometrical and mechanical properties of PA6/LDPE and PA6/HDPE blends

In this work, the influence of reactive compatibilizers on the rheometrical and mechanical properties of polyamide 6/low density polyethylene (PA6/LDPE) and polyamide 6/high density polyethylene (PA6/HDPE) blends was investigated. Polyethylene grafted with maleic anhydride (PEgMA), polyethylene grafted with acrylic acid (PEgAA), and ethylene-methyl acrylate-glycidyl methacrylate (EMA-GMA) were used as compatibilizers. The blends were characterized by torque rheometry, mechanical properties, and morphology. Rheometrical properties results show that PEgMA and PEgAA compatibilizers are more reactive with PA6 than EMA-GMA. Mechanical properties and scanning electron microscopy analysis results show that EMA-GMA compatibilizer is as effective as PEgMA and PEgAA for PA6/LDPE blend. For PA6/HDPE blend, PEgAA and EMA-GMA compatibilizers proved to be as effective as PEgMA. For PA6/HDPE blend compatibilized with PEgAA, an intriguing “web” or “bridge” like structure was observed.     

Tensile behaviors of polyamide 6/UHLE blends

In this article, tensile behaviors of polyamide 6 and polyolefin blends were studied. Differential scanning calorimeter (DSC) was used to investigate the melting behaviors of injection-molded specimens and corresponding post-tensile tested specimens. As a result, the content of polyolefin blend, water, and anneal time has strong incidences on tensile behaviors of polyamide 6 blends. Double yielding was found in several blends under different conditions. DSC results showed that there are changes of crystal structure during tensile deformation. Finally, the origin of double yielding is detected to be related to polyamide 6.     

n-HA/PA66/HDPE复合生物材料的制备和性能研究

应用纳米羟基磷灰石(n-HA)、聚酰胺66(PA66)和高密度聚乙烯(HDPE)制备了生物医用复合材料。用化学分析法、燃烧实验、热分析、AFM、IR、XRD对复合材料的组成和结构进行了分析,并对复合材料的力学性能进行了研究。结果表明所制备的复合材料组成均一,具有高强柔韧的力学性能,纳米羟基磷灰石、聚酰胺66、高密度聚乙烯三者之间产生了一定的相互作用,形成了稳定的界面结合。因此,该三元复合材料可能成为一种新型的骨修复材料,在生物医学材料的开发和应用研究中具有重要意义。     

正应力支配下混合顺序对PA6/HDPE/CNTs体系结构及性能的影响EI北大核心CSCD

利用自行研制的叶片式混炼装置,实现了正应力支配下聚合物复合体系的熔融共混。实验研究了混合顺序以及混合时间对高密度聚乙烯(HDPE)/尼龙6(PA6)/碳纳米管(CNTs)共混物的微观结构、流变特性、热性能及宏观力学性能的影响。结果表明:正应力支配作用能在短混合时间内实现PA6粒子和CNTs的均匀分散,分散效率高;相比于将HDPE,PA6,CNTs三者同时共混或者是先将PA6与CNTs混炼制成母料,再与HDPE共混这两种混合顺序,先将HDPE与CNTs混炼制成母料,再与PA6共混制得的共混物中分散相PA6粒径最小,分散更均匀,共混物的热性能以及力学性能更好。     

大直径PA6/PA66共聚物单丝的后拉伸性能

以PA6/PA66共聚物为原料,纺制大直径单丝。对大直径共聚尼龙单丝初生丝的后拉伸性能进行研究,主要分析拉伸温度、拉伸方式、拉伸倍率及其分配对单丝力学性能的影响,同时测定共聚尼龙单丝结构并与相关均聚物进行对比。研究了口模拉伸与常规拉伸对共聚尼龙单丝力学性能的影响。实验表明,采用二级拉伸方式时,最佳拉伸倍率为4.7倍,其中一级拉伸倍率占比85%。热水拉伸温度为90℃,热风拉伸温度为180℃。     

紫外线辐照HDPE／PA6共混物界面相互作用的研究

采用ＥＳＣＡ、Ｍｏｌａｕ实验、ＳＥＭ、ＤＳＣ、ＤＭＡ、抽滤分析、ＦＴ－ＩＲ和拉抻应力－应弯曲线，研究了紫外线辐照ＨＤＰＥ／ＰＡ６共混物的界面相互作用机理。结果表明，紫外线辐照下，ＨＤＰＥ分子链上引入Ｃ＝Ｏ、ＣＯＯＨ、－ＯＨ、－ＯＯＨ、－Ｃ－Ｏ－等极性基因；在与ＰＡ６熔融共混过程中， 的Ｃ＝Ｏ、ＣＯＯＨ等基团与ＰＡ６分子我寂的酰胺基或端胺基发生化学反应，生成ＨＤＰＥ－ＰＡ６共聚物。共聚物的形成增强了     

A study on compatibilization of AES/PA6 blends

Polyblends of Nylon 6 and AES were prepared and their mechanical properties and phase morphology examined. Two compatibilization techniques were evaluated: addition of a suitable block copolymer: poly(styrene-co-maleic anhydride) (SMA); AES functionalization with maleic anhydride (MA) through reactive extrusion. As a preliminary test for the compatibilizing efficiency, SMAs and PA6 were compounded in a Brabender mixer, recording the torque during the operations and evaluating, by solvent extraction, the amount of SMA grafted to PA6. However, when moving to the ternary blends AES/SMA/PA6, the highest value of notched lzod impact strength (290 J m^–1 versus 20 J m^–1) was found for an SMA sample containing 24% MA, which did not show the highest reactivity with PA6 in the preliminary test run. This finding suggests that not only the reactivity towards PA6, but also the miscibility with AES phase (the highest for the SMA product with 24% MA) must be taken into account when designing the best performing compatibilizer. On the other hand, AES functionalization with MA and DCP proved to be more successful and the resulting 50/50 blend with PA6 exhibited an outstanding value of notched Izod impact strength (1050 J m^–1)     

Phase structure and morphological variations induced by straining in injection-moulded samples of PA6/EVA blends: influence of molecular structure of EVA copolymers

The influence of molecular structure and composition of ethylene-co-vinyl acetate (EVA) copolymers, differing in molecular mass and, for a given molecular mass, in vinyl acetate content (wt/wt), on morphological and structural changes undergone by injection-moulded samples of Nylon 6 (PA6)/EVA blends during uniaxial tensile straining at room temperature up to sample rupture and on properties of such materials was studied. Direct correlations between molecular structure and composition of EVA copolymers and the shape and size of domains of dispersed phase and ultimate properties of PA6/EVA materials have been drawn. For the dumb-bell-shaped specimens strained just beyond the yielding point, it was found that the original layered structure was strongly modified by straining. Three layers were, in fact, generated: a skin surface, where no domains of EVA dispersed phase were observed, an outer layer, where the EVA domains were elongated along the draw direction assuming mainly cylindrical shape, and a core where the EVA phase was segregated in ellipsoidal-shaped domains having their major axis oriented along the draw direction. For the samples strained to break it was found that the PA6/EVA fibres showed a single glass transition temperature, whose value is lower than that found for the fibre of plain PA6, but higher than that shown by PA6 phase in the unstrained samples; such a value, moreover, tends to be decreased on increasing the vinyl acetate content along the EVA chain, irrespective of copolymer molecular mass. The calorimetric measurements performed revealed, moreover, a noticeable increase of the observed melting temperature values of EVA phase in PA6/EVA fibres. In the PA6/EVA samples strained to break, only two different layers were seen: an outer skin, free of EVA domains, and a core where the EVA dispersed phase segregated in ellipsoidal-shaped domains. The values of stress at break, _B, and of the elongation at break, _B, exhibited by PA6/EVA fibres were found to be lower than those shown by the plain PA6. The trends of _B and _B values against the EVA vinyl acetate content showed, moreover, that _B and _B values decreased with increasing vinyl acetate content along the copolymer chain.     

HDPE/尼龙-6/EAA共混体系反应增容作用的研究EI

通过Ｂｒａｂｅｎｄｅｒ、ＤＳＣ、ＳＥＭ和力学性能测试研究了在ＨＤＰＥ／尼龙－６共混过程中ＥＡＡ对体系的增容作用、力学性能以及结晶行为的影响。研究结果表明，在反应共混过程中，ＥＡＡ中丙烯酸链段与尼龙－６末端胺基发生了化学反应，就地形成的ＥＡＡ－尼龙－６接枝共聚物对ＨＤＰＥ／尼龙－６体系有增容作用，因而明显减小了相区尺寸，提高了拉伸强度。由于在共混过程中有接枝共聚物形成，明显降低了尼龙－６的结晶。     

电子束辐照对HDPE/PA6共混体系的影响

通过电子束辐照的方法，在高密度聚乙烯（HDPE）分子链上引入含氧极性基团，增加了HDPE分子的极性，改善了HDPE与PA6的界面相容性，本文通过FT－IR，SEM，接触角、DSC等方法对电子束辐照HDPE／PA6体系的界面相互作用及其对共混体系结构与性能的影响进行了研究，结果表明，HDPE经电子束辐照后，在其分子链上引入了含氧极性基团，提高了HDPE的极性，增加了表面自由能，从而改善了其与PA6界面相容性，随着辐照剂量的增大，PA6分散相的粒径变小，在HDPE基体中的分散更均匀。     

LCP微球对LCP/尼龙6共混体系力学性能的影响

制备了分散相呈球状微粒形貌的液晶聚合物/尼龙6 (LCP/PA6)共混体系,选用离聚物磺化聚苯乙烯锌盐(Zn-SPS)和反应性嵌段共聚物苯乙烯-马来酸酐共聚物(SMA)作为体系的增容剂,探讨了在相间相互作用得以改善时,利用LCP微球改善 LCP/尼龙6 共混体系韧性的可能性。试样受拉后的形貌观察表明,在增容体系中,LCP微球很好地镶嵌在尼龙6基体中,粒子脱落的空洞发生了较大的形变。力学性能测试结果表明,LCP的加入使材料的拉伸强度低于纯尼龙6,加入增容剂后共混材料拉伸强度有所提高,其中LCP/PA6 (质量比10/90)共混体系增容后的拉伸强度与纯尼龙6 相当。所研究的增容体系的拉伸断裂吸收能均比未增容体系有所增加。其中,当 LCP的质量分数为4%时,Zn-SPS增容体系的拉伸断裂吸收能比未增容体系和纯尼龙6分别增加了12%和62%;当LCP的质量分数为10 %时,SMA增容体系的拉伸断裂吸收能比未增容体系和纯尼龙6分别增加了46%和55%。表明在适当条件下,利用LCP微球可以在保持共混体系的拉伸强度的同时提高材料的韧性。     

有机蒙脱土调控ABS/PA6共混体系的共连续结构

采用熔融共混的方法制备了不同配比的有机蒙脱土(OMMT)填充丙烯腈-丁二烯-苯乙烯(ABS)/尼龙6(PA6)共混物。通过抽提、SEM、TEM、XRD等表征手段研究了OMMT在PA6相中的定向分散现象及共混体系相结构的演变规律。结果表明,OMMT可以定向分散在ABS/PA6共混物的PA6相中,使形成共连续结构的聚合物比例范围变宽;随着OMMT含量的增加,形成共连续结构所需的PA6的含量降低,同时相尺寸减小;OMMT的临界含量(m(OMMT))和形成共连续PA6的质量分数(m(PA6))存在近似的反比关系,其特征参数n值约为8,据此可根据共混体系中PA6的含量,推算形成相反转所需的OMMT添加量,为相关共混物的制备提供有益的借鉴。     

PA6/POE-g-MAH共混体系缺口冲击断裂机理研究

研究了PA6/POE-g-MAH共混体系缺口冲击断裂的裂纹萌生、裂纹扩展、冲击断面形貌及紧邻断面下方截面上的相形态.结果显示:随着POE-g-MAH质量分数增加,PA6/POE-g-MAH共混体系缺口冲击断裂发生脆韧转变,裂纹源由"中心辐射型"转变为"线型",裂纹扩展形貌由岩石状脆性断裂特征转变为具有横纹形貌的韧性断裂特征.在紧邻韧性断面下方的截面上可观察到网状形貌,可能是由被刻蚀掉的POE-g-MAH和冲击时基体微观破坏共同组成.在脆性断裂的截面上则无明显的网状形貌.PA6/POE-g-MAH共混体系的断面及截面形貌变化与其脆韧转变的逾渗行为完全对应.DSC分析认为POE-g-MAH提高POE-g-MAH/PA6共混物的缺口冲击韧性与其对PA6晶体结构的改变没有关系.     

两步法制备HDPE/PA6复合材料的结构和阻隔性能

先利用微层共挤出技术制备高密度聚乙烯（HDPE）/尼龙6（PA6）交替层状材料,并将其造粒,然后在不同的温度下对层状粒料进行模压和微量注塑成型制备HPDE/PA6片状共混物。通过扫描电镜和氧气渗透测试研究二次加工方法和温度对相形态和阻隔性能的影响。通过压板在200℃制备片状共混物,可以保留微层共挤出时形成的PA6片状结...     

紫外线辐照HDPE与尼龙－6共混材料结构与力学性能的研究

研究了紫外线辐照ＨＤＰＥ与ＰＡ６共混材料的微观形态、结晶结构、熔融行为及力学性能。ＳＥＭ、ＷＡＸＤ、ＤＳＣ结果表明，随紫外线辐照时间的增加，共混物中ＰＡ６的粒径减小，与基体作用加强，ＨＤＰＥ晶面间距增大，熔点、结晶度降低，熔程变窄。力学性能测试结果表明，紫外线辐照能明显提高共混材料（ｕＨＤＰＥ／ＰＡ６：９０／１０）的拉伸强度、断裂伸长率、拉伸断裂能和冲击强度。当辐照时间超过１４４ｈ由于ＨＤＰＥ热稳定性明显降低，共混过程中ＨＤＰＥ热降解严重，共混物的韧性突降。     

POE-g-MAH反应性增容HDPE/pA6共混合金的热致形状记忆性能

采用乙烯-辛烯共聚物接枝马来酸酐(POE-g-MAH)作为高密度聚乙烯(HDPE)/尼龙6(PA6)共混体系的反应性增容剂,通过熔融挤出制备出固定相具有物理交联结构的热致形状记忆合金。研究了组分含量,拉伸比和形变回复温度对合金的形变回复率和回复速率的影响。结果表明,POE-g-MAH的添加显著提高了共混合金的形状记忆性能,当组分配比为80/20/10(HDPE/PA6/POE-g-MAH),形变回复温度为135℃,拉伸比为75%时,试样形变回复率达到96.5%。     

Thermal and mechanical properties of HDPE/ionomer blends

The thermal behavior, tensile and tear strength of blends containing high density polyethylene (HDPE) and a sodium neutralized ethylene-methacrylic acid copolymer ionomer have been studied. It was found that each HDPE/ionomer blend had two well-separated melting peaks and two crystallization peaks, which indicates that the components of such a blend are immiscible with each other. The tensile behavior of the ionomer showed severe strainhardening just above the yield point, which leads to a lower elongation at break and a higher tensile strength than HDPE, possibly due to a network-like structure formation of ionic aggregates. The tensile properties of HDPE/ionomer blends were generally inferior to those of the pure components. Furthermore, the tensile properties exhibited severe negative deviation from linear additivity of properties, which is characteristic of incompatible blends. The negative deviation was also observed for tear strength of HDPE/ionomer blends. Observation of tear fracture surfaces of the blends showed fibrillar structure when ionomer content was relatively low. However, for the blends of higher ionomer composition much less fibrillation on the fracture surface was observed, which yields a higher value of tear energy. This is attributed to a network-like structure of the ionomer continuous phase of the blends.     

PA6/POE-g-MAH共混物在缺口冲击与缺口拉伸实验中的脆韧转变

用缺口冲击和缺口拉伸实验研究PA6/POE-g-MAH共混物的脆韧转变。结果显示,POE-g-MAH含量对共混物脆韧转变的影响主要是POE-g-MAH含量对裂尖局部应变速率的影响。在缺口冲击和缺口拉伸实验中,随着POE-g-MAH含量增加,裂尖附近参与变形的范围增大,导致局部应变速率降低。当局部应变速率降低至某临界值时,材料的断裂发生脆韧转变。在缺口拉伸实验中,随着拉伸速度增加,PA6/POE-g-MAH共混物发生脆韧转变的POE-g-MAH含量增加。这可能是拉伸速度与POE-g-MAH含量对PA6/POE-g-MAH共混物裂尖局部应变速率共同影响的结果。