Preparation of the HIPS/MA graft copolymer and its compatibilization in PA6/HIPS blends

The graft copolymer of high impact polystyrene (HIPS) grafted with malice anhydride (MA) (HIPS-g-MA) was prepared with melt mixing in the presence of a free-radical initiator. The grafting reaction was confirmed by IR analyses and the amount of MA grafted on HIPS was evaluated by a titration method. 1–5 wt% of MA can be grafted on HIPS. HIPS-g-MA is miscible with HIPS. Its anhydride group can react with the PA6 during melt mixing the two components. The compatibility of HIPS-g-MA in the HIPS/PA6 blends was evident. Evidence of reactions in the blends was confirmed in the morphology and mechanical properties of the blends. A significant reduction in domain size was observed because of the compatibilization of HIPS-g-MA in the blends of HIPS and PA6. The tensile mechanical properties of the prepared blends were investigated and the fracture surfaces of the blends were examined by means of the scanning electron microscope (SEM). The improved adhesion in a 16%HIPS/75%PA6 blend with 9%HIPS-g-MA copolymer was detected. The morphology of fibrillar ligaments formed by PA6 connecting HIPS particles was observed.     

PP/PA1010共混物的形态结构及力学性能的研究

利用红外光谱、扫描电子显微镜和力学测试等方法, 甲基丙烯酸环氧丙酯熔融接枝聚丙烯ＰＰ－ｇ－ＧＭＡ对不同组成的ＰＰ／ＰＡ１０１０共混物形态结构和力学性能的影响。     

HIPS-g-MA共聚物对HIPS/PC共混物相容性、形态和拉伸性能的影响

研究了HIPS／PC共混物的相容性及HIPS－MA对HIPS（30）／PC（70）共混物的相容性、形态和拉伸性能的影响。DSC研究结果表明，HIPS／PC共混物中PS的玻璃化转变温度（Tg)不随组成而变化，而PC的Tg随其质量分数的降低逐渐向低温移动，说明HIPS／PC是部分相容体系。通过DSC、扫描电镜形态观察和拉伸性能测试结果发现，当HIPS－g-MA的含量低于7．5％时，共混物的相容性改善不明显，当其含量达到7．5％时，对共混物有明显的乳化作用，说明饱和的界面浓度在7．5％左右。HIPS－g-MA接枝共聚物在HIPS（30）／PC（70）共混物中的增容作用可能是酯交换反应原位生成的嵌段共聚物所致。     

相容性对PA66/POE共混材料形态、微结构及力学性能的影响

采用SEM、TEM、DSC及材料力学性能实验方法研究了马来酸酐 ( MAH ) 接枝乙烯-辛烯共聚物弹性体 ( POE ) 对PA66/POE共混材料形态、微结构及力学性能的影响。结果表明:热引发官能化POE产物 ( POE-g-MAH ) 可显著改善PA66/POE共混材料的相容性,使材料分散相尺寸减小,分布均匀,且材料缺口冲击强度显著增大。实验发现,PA66/POE-g-MAH共混材料分散相的弹性体颗粒内部存在较多份量的有序结构,材料中的分散相颗粒具有明显促进结晶的作用,此作用引起PA66基体结晶温度增加,结晶度增大,并在分散相质量分数为15% 的脆韧转变条件下,达到极大值。试样熔体的冷却速率越快,则此种促进结晶的作用就越明显。      

Dielectric properties of polyarylate blends

Dielectric properties and molecular motion were studied by use ofdielectric spectroscopy and differential scanning calorimetry for twoblends, fully transesterificated polyarylate of bisphenol A withterephthalate/isophthalate (50/50) (PA)/polycarbonate of bisphenol A(PC) blends and PA/poly(ethylene terephthalate) (PET) blends. All thequenched PA/PC and PA/PET blends were amorphous and the glasstransition temperature (Tg) was varied with the blends ratioaccording to Gordon-Taylor equation. The PA/PET blends with more than60% of PET crystallized above the crystallization temperature. ThePA/PC and PA/PET blends showed two dielectric relaxations, above Tg and below Tg, which are related to a glasstransition and a local motion of short segment, respectively. The relaxation moved to lower temperatures as PC or PET contentincreases, reflecting the lowering Tg faithfully. In the PA/PETblends, the static (₀) and the limiting dielectricconstant (), and the increment () for the relaxation decreases with increasingtemperature and the decrease falled on one curve, independent of theblend ratio. Any ferro- and piezoelectricity were not observed fortwo blends.     

动态保压注射成型中POE-g-MAH 对PA1010-PP 共混物的增容作用

以马来酸酐接枝乙烯-辛烯共聚物(POE-g-MAH)作为增容剂, 采用熔体共混的方法制备了PA1010-PP共混物, 通过扫描电镜(SEM)、 力学性能和差示扫描量热(DSC)测试, 研究了动态保压注射成型中POE-g-MAH对PA1010-PP共混物的增容作用。力学性能测试结果表明, 在注射成型过程中施加剪切应力, 明显提高了共混物的拉伸和冲击性能。SEM结果表明, 剪切诱导制品产生多层次结构, 而且分散相相区尺寸显著减小, 分散更趋均匀, 相界面更加模糊。DSC结果表明, 剪切应力作用下, 当POE-g-MAH的质量分数达到15%时, PP出现2个结晶峰, 即出现异相成核结晶和均相成核结晶, PP均相成核结晶的出现从另一个方面表明动态试样中分散相PP尺寸小于静态试样。剪切应力作用下增容作用的提高归因于剪切应力作用下独特相形态的形成。      

Poly (D,L-lactic acid)/poly (∈-caprolactone) blend membranes: preparation and morphological characterisation

With the aim of exploring possible application of the concept of blend compatibilisation into the field of biodegradable membranes, a study of the influence of random copolymer poly(D,L-lactide-co--caprolactone) on the properties of corresponding homopolymer blends has been conducted. Blends of plain homopolymers and blends containing 5 and 10 wt% of a copolymer of suitable composition have been prepared in the melt and characterised for their molecular interactions using thermal, dynamic-mechanical, mechanical (tensile tests) and morphological analyses. The blends are characterised by a good dispersion of the poly--caprolactone (PCL) minor phase into the poly(D,L-lactic acid) (PDLLA) matrix and better mechanical properties compared to plain PDLLA, and such characteristics further improve when adding the copolymer. Microporous blend membranes consisting of PDLLA and PCL were then prepared by a phase inversion method and characterised by scanning electron microscopy. The addition of compatibilising agent led to a highly homogeneous structure, while in absence of compatibiliser a clear phase separation occurred.     

PA1010/MGEPR共混物的力学性能

尼龙1010是我国首创的一种性能优良的工程塑料，为提高其干戍 低温冲击韧性，用Brabender PLE331型塑化仪制备了PA1010／MGEPR共混物，讨论了配料方式，MGEPR用量，丁基橡胶用量，螺杆转速等对共混物冲击强度，拉伸强度等力学性能的影响，结果表明，如采用PA1010／MGEPR（2）和PA1010／MGEPR（4）共混体系，则冲击强度较PA1010有明显提高，当螺转速为37r/min-47r/min时，混合效果较好，当丁基橡胶为乙丙橡胶（EPR）含量的10％（质量）时，共混物的冲击强度优良。     

Rubber toughening of plastics

Electron microscopy of a high-impact polystyrene (HIPS) polymer, containing 8.5 wt% polybutadiene, shows that the volume fraction, , of composite rubber particles is 35%. The rubber particle size distribution has 8 median diameter of 1.6 µm. By making a series of blends between this HIPS and polystyrene, it is shown that Young's modulus decreases linearly with . Dilution with polystyrene results in a sharp drop in notched Charpy impact strength. The relevance of these data to the interpretation of structure-property relationships for a wide range of HIPS morphologies is discussed.     

PA6-66-1010/MCPA6复合材料的结构与性能

采用原位聚合法制备了三元共聚尼龙6-66-1010(PA6-66-1010)与原位浇铸尼龙6(MCPA6)的共混复合材料。利用差示扫描量热法(DSC)、动态热机械分析(DMA)、力学性能测试和扫描电子显微镜(SEM)表征复合材料的结晶熔融行为、动态力学性能、力学性能及断裂破坏形貌。结果表明,PA6-66-1010的加入,使得复合材料中MCPA6分子间的氢键作用减弱、分子链活动性增加;复合材料的结晶温度、熔融温度、结晶度随着PA6-66-1010含量的增加而下降;PA6-66-1010的加入,破坏了MCPA6分子间氢键的规整性,使得复合材料韧性得到提高而强度变化不大;当PA6-66-1010含量为10%时,复合材料断裂伸长率提高近6倍。     

PA6／UHMWPE／HDPE-g-MAH共混物反应增容作用的研究

通过DSC,SEM,Molau试验和力学性能测试,研究了PA6／UHMWPE共混过程中HDPE－g-MAH对体系的增容作用,力学性能及结晶行为的影响,结果表明,共混体系为热力这不相容体系,在熔融共混过程中,PA6和HDPE－g-MAH发生化学反应,生成的枝共聚物对PA6／UHWMPE体系有增容作用,分析性和界面形态以及力学性能明显改善,共混体系中两相的结晶行为亦发生变化,尼龙组分的熔融热焓明显下降。     

Effect of phase transitions in copper-germanium thin film alloys on their electrical resistivity

An investigation was carried out to study the phase transitions in Cu-Ge thin films (80–200 nm in thickness) containing 0, 5, 15, 20, 25, 30, 35, 40, 45 and 50 at% Ge, and the corresponding effects on electrical resistivity. For these films, the phase transitions were found to follow the sequence: -phase (disordered face centred cubic, fcc, solid solution); 5 at% Ge -phase (disordered hexagonal close packed, hcp); 15 at% Ge -phase + ₁-phase (ordered orthorhombic, Cu₃Ge); 20 at% Ge ₁-phase; 25 at% Ge (₁-phase + progressively increasing proportions of a disordered Ge-rich solid solution); 30–50 at% Ge. Germanium was found to have no marked effect on grain size of all films studied excluding grain boundaries as electron scattering centres. Transition of the -phase into the -phase was found to occur in a highly coherent manner, which could be related to the reduced stacking fault energy of Cu by the addition of Ge. Most evidence pointed out that the initial increase in resistivity within the -phase range was related to hcp scattering centres, which could be associated with a localized high concentration of Ge. At 15 at% Ge, the resistivity reached a maximum value of about 50 cm associated with the complete transformation of -phase into the -phase. With continued increase in Ge concentration, the resistivity was found to gradually decrease reaching a minimum value of about 10 at 25 at% Ge, which was correlated with complete transition of the -phase into the ordered ₁-phase (Cu₃Ge). It was shown that the superlattice of Cu₃Ge could directly be derived from the disordered -phase by minor atom rearrangement on the [0 0 0 1]_hcp plane. Even though, minor proportions of a Ge-rich solid solution containing a small concentration of Cu were formed at Ge concentrations above 25 at%, the minimum resistivity of 10 cm was maintained as the Ge concentration was increased to 35 at%. Subsequently, the resistivity was increased reaching about 46 cm at 50 at% Ge.     

Toughening mechanism of PA1010/ester-based TPU blends

To improve the notched impact strength of polyamide-1010 (PA1010), it was modified with a thermoplastic poly (ester urethane) elastomer (ester-based TPU). The notched impact strength of PA1010/ester-based TPU blends was investigated by using an impact tester and the fracture morphology of PA1010/ester-based TPU blends was investigated by means of SEM. In the impact experiments, it was found that the notched impact strength of the blends is obviously higher than that of pure PA1010, and the fracture surfaces of the blends show a corrugated and oriented structure. The results indicate that the brittle-to-tough transition of the blends occurs when the content of ester-based TPU is 20 wt.% and there is a new toughening mechanism, which is the multi-layer crack extension mechanism, besides the crazing with a shear-yield mechanism in the process of fracture for the blend samples under impact.     

热致液晶共聚酯/PA6/RSMA原位复合材料1.RSMA对热致液晶共聚酯/PA6共混体系的增容作用

选用Vectra A950热致液晶共聚酯（LCP）,制备热致液晶共聚酯（LCP）／聚酰胺6（PA6）／苯乙烯－马来酸酐无规共聚物（RSMA）三元共混物,采用注射成型的方法实现原位复合,测定复合材料的熔体流变性能,FTIR光谱,动态力学性质和共混物形态结构,研究了RSMA对聚酰胺6／热致液晶共聚酯共混体系的增容作用,结果表明,RSMA的加入提高了LCP／PA6共混体的熔体粘度：RSMA与LCP和PA6发生酯化,酰胺化反应,改善了LCP与PA6之间的相容性,使两者的玻璃化温度相互靠近,了LCP在PA6基体中的分散,增强了两者之间的界面粘接。     

Polyamide 6/ethylene-co-vinyl acetate blends: Morphology-properties relationships in injection moulded samples

The properties of injection moulded bars of blends of polyamide 6 with several samples of ethylene-vinyl acetate copolymer (EVA) differing in vinylacetate content, molecular mass and melt viscosity and with one sample of an ethylene-vinylacetate-acrylic acid terpolymer were investigated. Correlations between molecular structure of EVA copolymers, overall composition, mode and state of dispersion of minor component and impact behaviour of injection moulded sheets of PA6/EVA blends were established.     

PVC/PA1010/SBS-g-MAH共混体系研究

制备了ＳＢＳ－ｇ－ＭＡＨ接枝聚合物,并对其进行了表征,以ＳＢＳ－ｇ－ＭＡＨ作为ＰＶＣ／ＰＡ１０１０共混体系的增剂,对不同配比的ＰＶＣ／ＰＡ１０１０／ＳＢＳ－ｇ－ＭＡＨ共混体系的物理力学性能,流变性及差热性等进行了研究,结果表明,ＳＢＳ－ｇ－ＭＡＨ接枝聚合物对ＰＶＣ／ＰＡ１０１０共混体系起到了明显的增容作用,得到了缺口冲击强度及拉伸强度均较高的ＰＶＣ／ＰＡ１０１０／ＳＢＳ－ｇ－ＭＡＨ共混物。     

PA-6/ABS共混体系中加入SMA的反应型增容作用

加入少量苯乙烯－马来酸酐共聚物,能改善苯不相容的尼龙－６／ＡＢＳ共浊 系的相容性,提高其力学性能。文中共混物的熔体流变性能,ＤＳＣ表征及相结构观察,表明相容性的改善是在熔融共混过程中ＳＭＡ在ＰＡ－６和ＡＢＳ界面的的接枝反应得以实现。     

Precipitation of hydroxyapatite nanoparticles: Effects of precipitation method on electrophoretic deposition

Electrophoretic deposition is a low-cost, simple, and flexible coating method for producing hydroxyapatite (HA) coatings on metal implants with a broad range of thicknesses, from < 1 m to > 500 m. As for many other HA coating techniques, densification of electrophoretically deposited coatings involves heating the coated metal to temperatures above 1000 C. Metal substrates tend to react with HA coatings at such temperatures inducing decomposition at temperatures below 1050 C (decomposition for pure HA normally occurs above 1300 C). Therefore, densification of these coatings needs to be conducted at temperatures lower than 1050 C, and this necessitates the use of high-surface-area HA nano-precipitates, rather than commercially available pre-calcined powders, which densify at temperatures typically higher than 1200 C. HA nano-precipitates were prepared by three methods and deposited on metal substrates by electrophoresis: (1) the acid base method, which produced plate-like nano-particles with a 2.5:1 aspect ratio, and severely cracked coatings; (2) the calcium acetate method, which produced needle-like nano-particles with a 10:1 aspect ratio, and slightly cracked coatings; (3) the metathesis method, which produced rounded nano-particles with a 2:1 aspect ratio, and high-quality crack-free coatings. The results suggested that the less equiaxed the nano-particles, the more cracked the coatings obtained by the electrophoretic deposition technique.     

Reactive processing — property relationships in biodegradable blends useful for prosthesis application

Reaction injection moulding of blend samples of poly(-hydroxybutyrate-co--hydroxyvalerate) (PHBV) and poly--caprolactone (PCL) has been performed in the presence of peroxide. The blends are compared to mechanical PHBV/PCL blends obtained in the absence of peroxides. Differences in chemical physical and mechanical properties are interpreted on the basis of intergrafted species present in the peroxide-treated blends. The obtained blends are proposed as versatile materials for applications for bioresorbable prostheses.     

聚酰胺胺改性碳纤维/尼龙复合材料制备及性能

为改善碳纤维增强尼龙复合材料(CFRPA)的加工流动性和力学性能,采用聚酰胺胺(PAMAM)树枝状高分子作为改性剂,通过熔融共混制备出碳纤维(CF)增强尼龙66(PA66)复合材料。采用DSC、万能试验机和SEM分别对改性后PA66的结晶行为、CFRPA的拉伸性能及微观组织形貌进行测试表征。结果表明,添加PAMAM可以极大地改善PA66流动性,有效降低CFRPA熔融共混时的黏度。PAMAM添加量为PA66的1wt%时,PA66的结晶度最大(为12.75%)。熔融指数(MFR)提高至112 g/10 min,较未改性的PA66的MFR增长了814.47%。对应的不同CF含量的CFRPA熔融共混时的平衡扭矩均有所降低,且CF可均匀地分布在PA66基体中,当CF含量为40wt%时,CFRPA的拉伸强度最高,为118 MPa。