Revision total hip replacement using the cement-in-cement technique for the acetabular component : technique and results for 60 hips

The technique of femoral cement-in-cement revision is well established, but there are no previous series reporting its use on the acetabular side at the time of revision total hip arthroplasty. We describe the surgical technique and report the outcome of 60 consecutive cement-in-cement revisions of the acetabular component at a mean follow-up of 8.5 years (range 5-12 years). All had a radiologically and clinically well fixed acetabular cement mantle at the time of revision. 29 patients died. No case was lost to follow-up. The 2 most common indications for acetabular revision were recurrent dislocation (77%) and to compliment a femoral revision (20%). There were 2 cases of aseptic cup loosening (3.3%) requiring re-revision. No other hip was clinically or radiologically loose (96.7%) at latest follow-up. One case was re-revised for infection, 4 for recurrent dislocation and 1 for disarticulation of a constrained component. At 5 years, the Kaplan-Meier survival rate was 100% for aseptic loosening and 92.2% (95% CI; 84.8-99.6%) with revision for all causes as the endpoint. These results support the use of the cement-in-cement revision technique in appropriate cases on the acetabular side. Theoretical advantages include preservation of bone stock, reduced operating time, reduced risk of complications and durable fixation.

Estudio del proceso de hidrocraqueo catalítico de PB y HIPS vírgenes sobre 0,5%Pt/HBeta

[ES] Actualmente, los plásticos están presentes en multitud de aplicaciones debido a sus buenas propiedades y bajo coste. Sin embargo, el corto uso de algunas aplicaciones y la baja degradabilidad de estos materiales, provoca un problema medioambiental. Debido a que la disponibilidad de materias primas para la producción de polímeros es limitada y, además, cada vez se presta mayor atención a los asuntos medioambientales, es necesario cerrar el ciclo de vida de dichos materiales y centrarse en la reconversión de residuos plásticos a nuevos productos.

官能化LLDPE及其合金材料(LLDPE/HIPS)的制备及结构性能研究

本文采用核磁共振碳谱、电喷雾质谱研究LLDPE-g-AA接枝产物的链结构。电喷雾质谱显示所有的丙烯酸单体都发生自聚形成低聚物，核磁共振碳谱进一步证明了丙烯酸在聚乙烯链上形成支链，并且由于反应挤出过程中的高温作用，丙烯酸支链脱水形成酸酐。丙烯酸支链在聚乙烯的结晶过程中影响链段的规整性排列，并有可能充当成核剂，使得聚乙烯晶体随着接枝率的升高变得小而不规整。接枝产物的流变行为表明丙烯酸支链起到内增塑剂作用，降低接枝产物的表观粘度，有利于产物的后加工处理。由于接枝率低的缘故，我们采用角鲨烷模拟乙丙共聚物与马来酸酐进行接枝反应。在170℃，单体浓度为2%W/V，引发剂浓度为0.2%W/V下，体系中存在马来酸酐自聚和接枝一对竞争反应。但由于存在链转移，马来酸酐大部分以单个分子形式接在角鲨烷上。对于LLDPE/HIPS共混体系，我们采用不同于以外加增容剂的办法，直接在共混过程中加入路易斯酸，利用聚乙烯本身带有或降解过程中生成的少量双键与苯发生Friedel-Crafts烷基化反应。为了找到最佳反应条件，我们研究了不同AlCl_3含量、反应时间、反应温度对增容效果的影响。增容共混物的力学性能，特别是冲击强度和微观形态照片表明加入AlCl_3后，在PE/HIPS两相界面处生成接枝共聚物PE-g-HIPS，降低界面张力，改善共混性。由于增容剂只在两相界面处生成，因此加入AlCl_3对共混物中聚乙烯组分的热学性能和结晶性并没有太大影响。

PBT/HIPS枘混体系的结构与性能及生物隆解聚合物结晶性能的研究

以过氧化二异丙苯(DCP)为引发剂，甲基丙烯酸缩水甘油醋(GMA)为活性单体对HIPS进行熔融接枝，制得了功能化的高抗冲苯乙烯(HIPS－g－GMA）。比较HIPS－g－GMA和纯的HIPS的红外谱图，可以看到在HIPS－g－GMA的谱图上出现了一个新的吸收峰，即1730cm~(-1)处的C=O的伸缩振动吸收峰，它为接枝的GMA中的醋基基团的特征峰，因此可以确定GMA己经接枝到HIPS上。能谱分析也提供了相似的结论。同时研究了单体浓度和DCP用量对产物接枝率的影响。用化学滴定方法测定了接枝物的接枝率。随着GMA量的增加，接枝率也随之增加，当GMA用量超过14％时，接枝率趋于平缓；接枝率随DCP量增加而增加。采用DSC、SEM, WAXD, DMA及力学性能等方法和手段研究PBTIHIPS和PBT/HIPS-g-GMA二元共混体系的结晶、形态结构、动态力学性能及力学性能随组成的变化。当PBT为分散相，在增容体系中的PBT出现了分级结晶现象，结晶温度降低，这是由于分散相更为精细的结果。DMA结果表明，在PBTIHIP S-g-GMA体系中由于发生了化学反应，有接枝共聚物生成，体系中两个聚合物的Tg松弛均出现了较明显的降低，增容后体系的力学性能有显著提高。采用DSC, SEM, DMA及力学性能等方法和手段研究PBT/HIPS/HIPS-g-GMA三元共混体系的结构与性能。结果表明PBT无论是分散相还是连续相，HIPS-g-GMA的作用表现为：（1）对PBTIHIPS体系的熔融和结晶行为产生了明显的影响，使PBT的结晶速率变慢，结晶度降低，结晶尺寸分布变宽，结晶完善性变差；（2）改善了共混体系的相容性。未增容体系的形态结构为锐型界面，分散相粒子同基材相连接处清晰缝隙表明两组分间界面粘接很差，为典型的不相容两相形态结构；而加入功能化接枝物的体系的分散相粒子明显变小且分布均匀，甚至难以分辨两相结构的界面；（3）提高了体系的力学性能。在多官能团单体存在下，辐照对PBTIHIPS产生影响。（1）对共混体系的熔融和结晶行为产生影响，使共混体系中的PBT的熔点降低，熔程变宽，结品度下降，结晶速率变慢，结晶尺寸分布变宽，结晶完善性变差；（2）辐射引发多官能团单体反应，使体系的两个Tg松弛发生内移，表明体系的相容性得到改善；（3）当PBT为连续相时，辐射引发的多官能团单体反应对体系的形态结构影响不如化学增溶剂HIPS-g-GMA的效果显著，含有TMPTA的体系的形态结构要好于TAIL o当PBT为分散相，体系的形态结构变化很大，分散相尺寸明显变下小，且分布均匀；（4）辐射改性能提高PBT为分散相的共混体系的力学性能。利用DSC研究了不同成核剂对生物降解聚合物PHBV的结晶性能的彩响。结果表明：（1)添加的成核剂均能影响PHBV的结晶和熔融行为，提高PHBV的结晶速率和使PHBV的结晶更加完美；（2）所有的成核剂均能降低PHBV的结晶自由能；（3）成核剂对PHBV的影响依次为BN, talc, Tb_2O_3和La_2O_3。

Morphology and thermal and mechanical properties of PBT/HIPS and PBT/HIPS-g-GMA blends

The modification of high-impact polystyrene (HIPS) was accomplished by melt-grafting glycidyl methacrylate (GMA) on its molecular chains. Fourier transform infrared spectroscopy and electron spectroscopy for chemical analysis were used to characterize the formation of HIPS-g-GMA copolymers. The content of GMA in HIPS-g-GMA copolymer was determined by using the titration method. The effect of the concentrations of GMA and dicumyl peroxide on the degree of grafting was studied. A total of 1.9% of GMA can be grafted on HIPS. HIPS-g-GNU was used to prepare binary blends with poly(buthylene terephthalate) (PBT), and the evidence of reactions between the grafting copolymer and PBT in the blends was confirmed by scanning electron microscopy (SEM), dynamic mechanical analysis, and its mechanical properties. The SEM result showed that the domain size in PBT/HIPS-g-GMA blends was reduced significantly compared with that in PBT/HIPS blends; moreover, the improved strength was measured in PBT/HIPS-g-GMA blends and results from good interfacial adhesion. The reaction between ester groups of PBT and epoxy groups of HIPS-g-GMA can depress crystallinity and the crystal perfection of PBT.

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.

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

HIPS的官能化及HIPS/PBT共混体系的研究

以过氧化二异丙苯 (DCP)为引发剂 ,甲基丙烯酸缩水甘油酯 (GMA)为活性单体 ,高抗冲苯乙烯(HIPS)通过熔融接枝制得了功能化的高抗冲聚苯乙烯接枝物 (HIPS g GMA)。用红外光谱和电子能谱对其结构进行了表征。HIPS g GMA的红外谱图 ,证明GMA已经接枝到HIPS上。电子能谱分析也提供了相似的结论。研究了单体浓度和DCP用量对产物接枝率的影响 ,并用化学滴定方法测定了接枝物的接枝率。用DSC、SEM、WAXD、DMA等研究了PBT/HIPS和PBT/HIPS g GMA的结晶、形态结构、动态力学性能及力学性能随组成的变化。SEM及DMA分析表明增容后体系的相容性得到改善 ,力学性能有较大提高。

Morphology, crystallization behaviors, and mechanical properties of PA1010/HIPS and PA1010/HIPS-g-MA blends

The binary blends of polyamide 1010 (PA1010) with the high-impact polystyrene (HIPS)/maleic anhydride (MA) graft copolymer (HIPS-g-MA) and with HIPS were prepared using a wide composition range. Different blend morphologies were observed by scanning electron microscopy according to the nature and content of PA1010 used. Compared with the PA1010/HIPS binary blends, the domain sizes of dispersed-phase particles in PA1010/HIPS-g-MA blends were much smaller than that in PA1010/HIPS blends at the same compositions. It was found that the tensile properties of PA1010/HIPS-g-MA blends were obviously better than that of PA 1010/HIPS blends. Wide-angle xray diffraction analyses were performed to confirm that the number of hydrogen bonds in the PA1010 phase decreased in the blends of PA1010/HIPS-g-MA. These behaviors could be attributed to the chemical interactions between the two components and good dispersion in PA1010/HIPS-g-MA blends.

Effect of compatibilization on the properties of HIPS/PA1010 blends

Blends consisting of high-impact polystyrene (HIPS) as the matrix and polyamide 1010 (PA1010) as the dispersed phase were prepared by mixing. The grafting copolymers of HIPS and maleic anhydride (MA), the compatibilizer precursors of the blends, were synthesized. The contents of the IMA in the grafting copolymers are 4.7 wt % and 1.6 wt %, and were assigned as HAM and LMA, respectively. Different blend morphologies were observed by scanning electron microscopy (SEM); the domain size of the PA1010 dispersed phase in the HIPS matrix of compatibilized blends decreased comparing with that of uncompatibilized blends. For the blend with 25 wt % HIPS-g-MA component, the T-c of PA1010 shifts towards lower temperature, from 178 to 83 degrees C. It is found that HIPS-g-MA used as the third component has profound effect on the mechanical properties of the resulting blends. This behavior has been attributed to the chemical reaction taking place in situ during the mixing between the two components of PA1010 and HIPS-g-MA. (C) 2000 John Wiley & Sons, Inc.

Radiation effects on the immiscible polymer blend of nylon1010 and high-impact polystyrene (HIPS) I: Gel/dose curves, mathematical expectation theorem and thermal behaviour

This paper studies the radiation properties of the immiscible blend of nylon1010 and HIPS. The gel fraction increased with increasing radiation dose. The network was found mostly in nylon1010, the networks were also found in both nylon1010 and HIPS when the dose reaches 0.85 MGy or more. We used the Charleby-Pinner equation and the modified Zhang-Sun-Qian equation to simulate the relationship with the dose and the sol fraction. The latter equation fits well with these polymer blends and the relationship used by it showed better linearity than the one by the Charleby-Pinner equation. We also studied the conditions of formation of the network by the mathematical expectation theorem for the binary system. Thermal properties of polymer blend were observed by DSC curves. The crystallization temperature decreases with increasing dose because the cross-linking reaction inhibited the crystallization procession and destroyed the crystals. The melting temperature also reduced with increasing radiation dose. The dual melting peak gradually shifted to single peak and the high melting peak disappeared at high radiation dose. However, the radiation-induced crystallization was observed by the heat of fusion increasing at low radiation dose. On the other hand, the crystal will be damaged by radiation. A similar conclusion may be drawn by the DSC traces when the polymer blends were crystallized. When the radiation dose increases, the heat of fusion reduces dramatically and so does the heat of crystallization. (C) 1999 Elsevier Science Ltd. All rights reserved.

The compatibility and morphology of HIPS/PC and HIPS-g-GMA/PC blends

The compatibility and morphology of HIPS/PC and HIPS-g-GMA/PC blends were studied. The compatibility and morphology of HIPS/PC blends were characterized by DSC and SEM, respectively. The result of DSC shows that T-g of PS doesn't change with the blend composition, and T-g of PC decreases with the increase in weight fraction of HIPS, which indicates that the PC/HIPS blend is a partially miscible system. Results of SEM indicate that the decrease in T-g of PC results from PS interpenetrating into the phase of PC, and no change in T-g of PS results from PC not interpenetrating into the phase of PS. The copolymer of HIPS-g-GMA was prepared by reactive grafting method. The IR spectrum shows that GMA is grafted on the chain of HIPS. The compatibility and morphology of HIPS-gGMA (35)/PC (65) were studied by DSC and SEM. PC (65)/HEPS-g-GMA (35) blend exhibits reduced size of disperse phase, enhanced interface adhesion and lower T-g of PC phase as compared with the PC(65)/HIPS(35) blend. It implies that HIPS-g-GMA is an effective compatibilizer of the HIPS/PC blend.