Friedel-Crafts烷基化反应就地增容PP/PS合金

考察了无水AlCl3用量对PP、PS大分子间Frledel-Crafts烷基化反应及PP/PS合金性能的影响.通过对加入无水AlCl3后PP/PS合金力学性能和界面形态的研究表明:加入适量的无水AlCl3(0.4%)可以引发PP、PS间的Friedel-Crafts烷基化反应,生成的PP-g-PS接枝物能起到就地增容PP/PS的作用,使合金的力学性能得到显著提高;当加大AlCl3用量后,由于其引起的PS分子链的断链反应起主导作用,合金的性能反而会降低.     

PMMA/PEG共混物形态和热性质的研究

在聚乙二醇存在的情况下,自由基聚合得到的聚甲基丙烯酸甲酯/聚乙二醇(PMMA/PEG)共混物,是一种半结晶聚合物;有相分离发生,一部分PEG晶体依然保持其晶体的特征,另一部分PEG晶体转变成非晶态,与PMMA网络复合,形成完全均一的非晶相。     

A modified model predictions and experimental results of weld-line strength in injection molded PS/PMMA blends

In this paper, the model based on melt diffusion and Flory-Huggins free energy theory for predicting the weld-line strength of injection molded amorphous polymers and polymer blends parts were modified by considering the diffusion thickness in the interface as a function of contact time. The modified model for weld-line strength prediction of homopolymers and polymer blends were, respectively, used to evaluate the weld-line strength of Polystyrene (PS) and Poly(methylmethacrylate) (PMMA), and that of PS/PMMA blends. The model predictions show that the theoretic predictions as a function of temperature and contact time for PS, PMMA and PS/PMMA (80/20, 70/30) are in good agreements with corresponding experimental results. However, the model predictions for PS/PMMA (20/80, 30/70) blends are much higher than experimental results. The morphology in weld-line regions for PS/PMMA (20/80, 30/70) shows lack of dispersed PS phase. Near the weld-line regions, dispersed PS phase is highly oriented along the weld-line. In theoretic prediction for polymer blends, three kinds of diffusion: Polymer A-Polymer A and Polymer B-Polymer B self-diffusions and Polymer A-Polymer B mutual diffusion were considered. This is why model predictions for PS/PMMA (20/80, 30/70) blends are higher than experimental results.     

PS/PMMA共混物中超声波传播特性研究

利用自行设计的装置,采用改变入射角的方法将超声波纵波和横波导入不相容的聚苯乙烯/聚甲基丙烯酸甲酯(PS/PMMA)共混物体系中。研究了两种波的声速和声衰减随共混体系共混比变化的情况,并结合扫描电子显微镜(SEM)检测得到的相畴尺寸进行了分析。结果表明:共混物中的相畴尺寸与其散射衰减之间存在对应关系;由于横波波长更为接近共混体系中的相畴尺寸,横波的散射衰减明显大于纵波。     

PVA／PS共混改性及对拉伸性能的影响

对不同配比的聚乙烯醇／聚苯乙烯（PVA／PS）共混物进行共混改性研究。使用拉力试验机测试了PVA／PS共混物的拉伸强度,使用扫描电镜（SEM）分析试样的断口,并分析共混物的分散性及相容性。实验结果表明：PVA含量在10％以内对共混物的拉伸强度影响不大,主要表现为PS的拉伸强度;而PVA含量在10％～50％的范围内,扛伸强度明显下降,在50％时达到最小值。     

The Effect of Multiple Compatibilizers on the Impact Properties of Polypropylene/Polystyrene (PP/PS) Blend

Effects of compatibilizers on impact properties of polypropylene/ polystyrene (PP/PS) blends were studied and carried out through melt blending using co- rotating twin-screw extruder. A combination of two compatibilizers, maleic anhydride grafted polypropylene (PP-g-MA) and styrene maleic anhydride (SMA) was applied into PP/PS blends. Results from the Izod impact strengths, SEM observations and contact angle measurements in PP(50)/PS(50) blends indicated a better compatibilization effect with the use of dual compatibilizers. This was most probably due to improved adhesion between phases in PP/PS blend systems. The use of dual compatibilizers in the blend compositions produced higher impact properties in the PP/PS blend systems compared to single compatibilizer system.     

反应型增容剂PS-co-GMA在PA1010/ABS共混体系中的增容作用

以ＰＳ－ｃｏ－ＧＡＭ作为ＰＡ１０１０／ＡＢＳ共混体系的增容剂,探讨了增容剂的含量对共混体系力学性能的影响,同时,利用熔融共混法制备了ＰＡ１０１０／ＡＢＳ－ｇ－ＧＭＡ共混体系,比较了两种增容方式对共混体系力学性能的影响。     

不溶混聚合物共混体系相态反转的研究进展

对不溶混聚合物共混体系相态反转的粘度比模型、弹性比模型、粘弹性比模型和扭矩比模型进行了分析，提出了动态硫化EPDM／PP等热塑性弹性体相态反转的判断方法，认为振动力场对控制不溶混聚合物共混体系的相态反转具有积极作用。     

废报纸粉填充聚丙烯材料的研究

本文介绍废报纸粉填充聚丙烯（ＰＰ）的研制。通过在体系中加入高分子偶联剂马来酸酐（ＭＡＨ）接枝ＰＰ（ＭＡＰＰ）来改善纸粉与ＰＰ基体的相容性，并针对纸粉填充后材料变脆的问题，用乙丙橡胶（ＥＰＤＭ）和乙烯醋酸乙烯共聚物（ＥＶＡ）对材料进行增韧，均取得显著的效果。所制材料的纸粉填充量（质量分数）可高达５０％～６０％，价廉、质轻、其主要性能好于桑塔纳轿车用木粉填充ＰＰ板，可望有较好的应用前景。当纸粉填充量（质量分数）为４０％～５０％时，主要性能：弯曲强度６９．０１～７４．８３ＭＰａ，杨氏弯曲模量２６４０～２９９６ＭＰａ，冲击强度１３．２５～１３．５０ｋＪ／ｍ２。     

PMMA-g-PS对CPE/PS共混体系性能的影响

采用大单体技术合成聚苯乙烯和甲基丙烯酸甲酯的规整接枝共聚物PMMA-g-PS。研究了共聚合反应条件聚苯乙烯大单体的投料质量分数、引发剂用量、反应温度对接枝效率的影响;研究PMMA-g-PS作为CPE/PS体系的共混增容剂时,共混物的组成、接枝物的用量、接枝物的组成对共混物物理机械性能的影响。用SEM,DSC表征共混物的变化,结果表明,接枝共聚物能促进两组分相容,起到增容剂的作用。     

影响HDPE/PS/PMMA三元体系核壳形态的因素

通过密炼得到高密度聚乙烯(HDPE)、聚苯乙烯(PS)和聚甲基丙烯酸甲酯(PMMA)三元体系核壳结构。用扫描电镜(SEM)考察了组分配比、增容剂氢化苯乙烯-丁二烯-苯乙烯弹性体(SEBS)和退火对体系核壳形态的影响。结果表明,组分用量最大的HDPE总是形成基体相,而PS形成壳,PMMA形成核;核壳粒子的尺寸和内部结构随组分用量而变化,随着分散相用量(PS+PMMA)增加,核壳粒子间碰撞融合机会增多,因此核壳粒子尺寸变大,同时核壳粒子由一核一壳逐渐转变为多核一壳结构;而随着核壳粒子中PS用量增加,PMMA核的尺寸显著减小;增容剂SEBS的加入,抑制了共混中核壳粒子间的融合,导致核和壳的尺寸减小;200℃下退火处理使分散相向体系自由能更小的一核一壳结构转变。     

填料改性SBS热塑性弹性体的研究

研究了不同填料以及改变填料用量、补强体系分别对热塑性弹性体ＳＢＳ各种性能的影响，并测定了最佳配方的挤出性能及工艺条件。结果表明，白炭黑的适量加入对ＳＢＳ的撕裂强度有显著提高，适量活性钙可提高ＳＢＳ的拉伸强度和撕裂强度，聚烯烃填料作为填充剂可以降低胶料的成本。该配方主要适用鞋底料的研究。     

HDPE-g-GMA反应性增容PA66/UHMWPE共混合金性能研究

以甲基丙烯酸缩水甘油酯接枝高密度聚乙烯(HDPE-g-GMA)作为聚酰胺66/超高摩尔质量聚乙烯(PA66/UHMWPE)共混合金的增容剂,采用熔融法制备了PA66/uHMwPE/HDPE-g-GMA共混合金.通过Molau试验、SEM观察和力学性能测试,研究了HDPE-g-GMA在熔融共混过程中对PA66/UHMWPE共混合金的增容作用.结果表明:HDPE-g-GMA与PA66发生了化学反应,所生成的接枝共聚物对PA66/UHMWPE共混合金有较好的增容作用;PA66/UHMWPE共混合金的界面形态和力学性能均有较大改善,吸水率也有所降低.     

PC／PS共混物流变行为的研究

本文考察了聚碳酸酯／聚苯乙烯（ＰＣ／ＰＳ）共混物的流变行为与力学性能。研究发现：ＰＳ的加入，可使共混体系的粘流活化能降低，改善了ＰＣ加工时对温度的依赖性。ＤＳＣ分析证实随着ＰＳ含量的增加，体系玻璃化温度逐渐下降，说明ＰＣ与ＰＳ是部分相容的。当ＰＳ用量在１０％以内时，共混物的拉伸强度和缺口冲击强度均高于纯ＰＣ的力学性能，而且随着ＰＳ含量的变化，两者均出现峰值，取得了既增韧又增强的双重效果。共混体系的表观粘度ηａ随剪切速率增大而下降，且高剪切速率下ηａ下降更快；ＰＳ含量增加，流动曲线向下移动，表观粘度下降，意味着流动性增加，减小了体系的流动阻力     

Effect of ultrasonic oscillations on weld line strength of PS,PMMA, and their blends

The effect of ultrasonic oscillations on the weld line strength of amorphous polystyrene (PS), polymethyl methacrylate (PMMA), and PS/PMMA (20/80, 50/50, 80/20) blends at various temperatures was investigated. By facilitating the molecular diffusion across the weld line, the introduction of ultrasonic oscillations could evidently improve the weld line strength of PS, PMMA, and their blends. The different effects on the weld line strength of PS/PMMA (20/80, 50/50, 80/20) blends were investigated. The ultrasonic oscillations could greatly increase the weld line strength of PS/PMMA (80/20) by ～ 70%, but was less efficient to PS/PMMA (50/50, 20/80) blends, due to the great difference of weld line morphologies of these blends. The dispersed phase of PS/PMMA (80/20) in the weld line was spherical while two different morphologies in the weld line of PS/PMMA (50/50) were observed. And the stripe‐like morphology of PS perpendicular to the flow direction in the weld line of PS/PMMA (20/80) is responsible for the little effect of ultrasonic oscillations. The fractured surfaces of PS, PMMA, and PS/PMMA (80/20) with weld line became much rougher due to the introduction of ultrasonic oscillations. The morphology study of PS/PMMA (80/20) showed that the spherical dispersed phase of PS/PMMA at the skin turned smaller under ultrasonic oscillations. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2990–2997, 2006     

PE-LLD-g-(GMA-co-St)对PLA/PE-LLD共混体系的反应性增容研究

在聚乳酸(PLA)中加入线形低密度聚乙烯(PE-LLD)进行增韧,并通过相容剂 PE-LLD-g-(GMA-co-St)增容PLA 和 PE-LLD。采用红外光谱、动态流变测试和扫描电子显微镜对共混物进行了表征,测试了共混物的冲击强度。结果表明,加入 PE-LLD-g-(GMA-co-St)能明显提高 PLA/PE-LLD 的冲击韧性,最高比 PLA/PE-LLD 简单共混物提高了144%,熔体的损耗模量G″明显增大,PE-LLD 分散相在 PLA 基体中有更加细微的分散,界面更加模糊,PE-LLD-g-(GMA-co-St)在共混体系中起到了反应性增容作用。     

端基官能化PEG与PMMA共混薄膜表面接触角的研究

使用硅酸酯和聚乙二醇单甲醚(mPEG)反应制得端基官能化的PEG大分子,然后将此分子与聚甲基丙烯酸甲酯(PMMA)在氯仿溶液中共混,在玻璃基板上旋转涂膜后对涂膜的表面接触角进行了研究。实验发现,官能化的mPEG在低添加量时就可有效降低体系的接触角。对不同分子量的PEG测试结果表明,在同等添加质量比情况下,低分子量的官能化mPEG表现出更好的表面改性效果,这主要是由于低分子量的PEG有较高的硅烷氧基摩尔比例和较强的运动能力所致。研究结果表明,表面接触角的降低是由于PEG分子的硅氧烷端基在PMMA表面富集造成的。     

苯乙烯/聚丙烯酸钠原位聚合物的水崩解性研究

将苯乙烯、交联聚丙烯酸钠吸水树脂微粒、表面活性剂及引发剂配成非水溶剂悬浮液,采用原位共混聚合法制备了能够遇水崩解的环境友好材料苯乙烯/聚丙烯酸钠共混物;考察了聚丙烯酸钠交联微粒的添加量、表面活性剂对共混材料水崩解性能的影响,观察了材料崩解前后的微观形态,并在此基础上提出了苯乙烯/聚丙烯酸钠交联微粒原位聚合共混物的水崩解机理.结果表明苯乙烯/聚丙烯酸钠交联微粒原位聚合共混物遇水时,聚苯乙烯因交联聚丙烯酸钠微粒吸水膨胀而崩解破坏或失去机械强度.     

PS/PMMA共混体系的挤出流变行为

利用单螺杆挤出机,配备特殊设计的狭缝模头,在不改变螺杆转速的情况下获得流经口模的不同流量,研究了聚苯乙烯(PS)/聚甲基丙烯酸甲酯(PMMA)共混体系的挤出流变行为。结果表明,PS/PMMA共混物熔体的流变行为和其组分熔体的流变行为类似,都表现出假塑性流体的流动行为;在所研究的组成范围内,共混物熔体的非牛顿指数低于任一组分熔体。随着共混物黏度比的减小,其熔体的非牛顿指数呈下降的趋势;共混物熔体的黏度对加和性法则皆表现为负偏差,表明在界面处具有弱的相互作用。     

Surface feature size of spin cast PS/PMMA blends

Thin films of polystyrene (PS)/polymethylmethacrylate (PMMA) blends have been spin cast on mica from chloroform solutions. When the concentration of PMMA in the casting solution is less than that of PS a pitted morphology is formed. The average sizes of the pits are shown to increase with both the total concentration of the casting solution and the relative concentration of PMMA. The change in pit size is explained in terms of incomplete dewetting of a PMMA solution from an underlying PS solution. For a given ratio of PMMA/PS the average pit diameters appear to increase linearly with the square of the film thickness, the gradient of which is dependent on the film composition.