A Novel Polymethyl Methacrylate (PMMA)-TiO_2 Nanocomposite and Its Thermal and Photic Stability

A new kind of polymethyl methacrylate （PMMA）-TiO2 nanocomposite was synthesized through polymerization. The thermal and photic stability of this PMMA TiO2 nanocomposites were investigated. The as prepared samples were characterized by scanning electron microscopy （SEM）, UV-Vis spectroscopy, differential thermal analysis （DTA） and the photo-induced weight loss, The results show that the photostability of the PMMA-TiO2 nanocomposite is higher than that of the pure PMMA under UV-light irradiation, The weight loss of the pure PMMA reaches 30 % after 300 h UVirradiation, while the composite only 0.3% under the identical experimental condition. The glass transition temperature （TR） of pure PMMA is only 80℃, while the Tg of the composite reaches 258℃. Compared with pure PMMA, the thermal stability of the composite is greatly enhanced.

Injectable bioactive polymethyl methacrylate-hydrogel hybrid bone cement loaded with BMP-2 to improve osteogenesis for percutaneous vertebroplasty and kyphoplasty

Poly methyl methacrylate(PMMA)bone cement is used in augmenting and stabilizing fractured vertebral bodies through percutaneous vertebroplasty(PVP)and percutaneous kyphoplasty(PKP).However,applications of PMMA bone cement are limited by the high elasticity modulus of PMMA,its low biodegradability,and its limited ability to regenerate bone.To improve PMMA bio activity and biodegradability and to modify its elasticity modulus,we mixed PMMA bone cement with oxidized hyaluronic acid and carboxymethyl chitosan in situ cross-linking hydrogel loaded with bone morphogenetic protein-2(BMP-2)to achieve novel hybrid cement.These fabric ated PMMA-hydrogel hybrid cements exhibited lower setting temperatures,a lower elasticity modulus,and better biodegradability and biocompatibility than that of pure PMMA cement,while retaining acceptable setting times,mechanical strength,and inj ectability.In addition,we detected release of BMP-2 from the PMMA-hydrogel hybrid cements,significantly enhancing in vitro osteogenesis of bone marrow mesenchymal stem cells by up-regulating the gene expression of Runx2,Coll,and OPN.Use of PMMA-hydrogel hybrid cements loaded with BMP-2 on rabbit femoral condyle bone-defect models revealed their biodegradability and enhanced bone formation.Our study demonstrated the favorable mechanical properties,biocompatibility,and biodegradability of fabricated PMMA-hydrogel hybrid cements loaded with BMP-2,as well as their ability to improve osteogenesis,making them a promising material for use in PKP and PVP.

Effect of Methyl Methacrylate– Acrylonitrile -Butadiene–Styrene (MABS) on the Mechanical and Thermal Properties of Poly (Methyl Methacrylate) (PMMA)-Fly Ash Cenospheres (FAC) Filled Composites

With the advent of plastics and the wide range of fillers that are available have made modifications as precise as the tailored resins themselves. To modify the properties of polymer either by using fillers or by preparation of polymer blends gives rise to new materials with tailored properties. More complex, three-component systems, obtained by the addition of polymeric modifier to polymer filled composites may be of interest. Use of Fly ash cenospheres is very attractive because it is inexpensive and its use can reduce the environmental pollution to a significant extent. In the present study, Poly (Methyl Methacrylate) (PMMA)-Fly ash cenospheres composites were prepared using extrusion followed by Injection molding. The effect of matrix modification with Methyl methacrylate– acrylonitrile -butadiene–styrene (MABS) on the performance of PMMA- Fly ash cenospheres compositions was also, studied. It was found that with the addition of Fly ash cenospheres particulate as filler in PMMA showed marginal reduction in Tensile Strength, % Elongation and Impact strength and improvement in Flexural Strength, Heat Deflection Temperature and Vicat Softening Point. Compared with PMMA-cenospheres composites, the notched Impact Strength of the PMMA/MABS/cenospheres composites showed marginal enhancement in values at higher loading of cenospheres. The optimum performances in mechanical and thermal properties were obtained when the ratio of MABS to cenospheres was 1:2.

Measurement of Secondary Electron Energy Spectra of Polymethyl Methacrylate

We report on a novel and convenient method of measuring secondary electron spectra for insulators in a secondary electron yield measurement system with a planar grid analyzer configuration and a metal mesh probe. In this measurement, the planar grid is negatively biased to force some emitted secondary electrons to return to the sample surface and to neutralize charges accumulated on the sample during the previous beam irradiation. The surface potential of the sample is then measured by use of a metal mesh probe. The grid bias for neutralization corresponding to the zero surface potential is determined based on the linear relationship between the surface potential and the grid bias. Once the surface potential equals zero, the secondary electron spectra of polymethyl methacrylate（PMMA） are studied experimentally by measuring the -curve and then fitting it to Everhart＇s formula. The measurement results show that the peak energy and the full width at half maximum of the spectra are 4.26 eV and 14.06 eV, respectively.

A Novel Method for Preparing Approximately Micron-sized Polymethyl Methacrylate Microspheres with Clear Surface

Polymethyl methacrylate (PMMA) microspheres with clear surface and diameter close to 1 祄 were synthesized by newly soap-free emulsion polymerization. The results showed that the presence of ethanol and NaCl made the increase of diameter and distribution, while the presence of toluene could avoid the problem of the increase of distribution, resulting a harvest of PMMA microspheres with a diameter close to 1 祄.

Epiphyseal distraction and hybrid reconstruction using polymethyl methacrylate construct combined with free non-vascularized fibular graft in pediatric patients with osteosarcoma around knee: A case report

BACKGROUND In children with osteosarcoma around the knee joint without epiphysis involvement,joint-sparing surgery seems to be an ideal way to retain knee joint function.However,there are two points of debate with regard to the technique:How to accurately achieve a safe surgical margin,and how to achieve intercalary reconstruction of the massive bone defect following resection of the tumor.CASE SUMMARY We present the case of an 8-year-old girl with osteosarcoma of the distal femur without involvement of the epiphysis.Epiphyseal distraction was applied to separate the epiphysis and metaphysis,and this provided a safe surgical margin.The massive bone defect was reconstructed with a custom-made antibioticloaded polymethyl methacrylate(PMMA)construct combined with a free nonvascularized fibular graft.Six months after surgery,bone union between the autograft and host bone was confirmed in both the proximal and distal femur by computer tomography(CT)examination.Moreover,considerable callus formation was found around the PMMA construct.After 28 mo of follow-up,there was no sign of recurrence or metastasis.The patient could walk without any aid and carry out her daily life activities satisfactorily.CONCLUSION In cases of osteosarcoma without epiphysis involvement,epiphyseal distraction can be easily applied to obtain a safe margin.Hybrid reconstruction with an antibiotic-loaded PMMA construct combined with a free non-vascularized fibular graft has the advantages of being easy to manufacture,less time-consuming to place,and less likely to get infected,while also ensuring bone union.Our case provides an alternative technique for biological reconstruction after joint-sparing surgery in patients with osteosarcoma around the knee without epiphyseal involvement.

Preparation and Fluorescence Properties of Polymethyl Methacrylate Resin Incorporated with Sodium Tris (Pyridine Dicarboxylato) Europate

Based on the strong fluorescence and the highly thermal stability of sodium tris (pyridine dicarboxylato) europate (Na 3Eu(DPA) 3), polymethyl methacrylate (PMMA) composite material incorporated with the complex, PMMA: Na 3Eu(DPA) 3, was prepared at 250 ℃. The fluorescence behavior of PMMA: Na 3Eu(DPA) 3 material was examined. The results show that the composite material keeps the luminescent characteristics of the Eu 3+ chelate after PMMA is incorporated with Na 3Eu(DPA) 3, and strong orange-red emission of the composite was observed. The fluorescence intensity of the composite material increases with the increase of the weight ratio of Na 3Eu(DPA) 3 to PMMA, but the relationship is not linear.

本体聚合PMMA基复合介质膜的储能特性研究

目前有机薄膜电容器中的介质材料多为线性电介质,这类聚合物的介电常数通常较低,造成电容器储能密度普遍偏低,而新型高储能聚合物介质材料一般又存在介质损耗高的问题。聚甲基丙烯酸甲酯(PMMA)与高储能含氟聚合物的相容性较好,常被用来改善后者的力学和击穿性能,但市售的PMMA存在本征介质损耗过高的问题。为了降低PMMA的介质损耗,本文用甲基丙烯酸甲酯(MMA)与苯乙烯(St)合成MMA-St共聚物(MS),将不同比例的MS掺入本体聚合的PMMA中形成复合体系,并研究复合体系的介电特性、储能特性及绝缘特性。结果表明:该复合体系可以显著降低PMMA的介质损耗,相较于PMMA更适合作为高储能聚合物的改性材料。其中复合10%MS的介质膜在5 500 kV/cm电场下获得了5 J/cm^(3)的放电能量密度,充放电效率达到83%。

Effect of local massage on prevention and treatment of intra-arterial polymethyl methacrylate embolism complications:An experimental animal study

Background:Massage is generally believed to be a simple and effective method for preventing necrosis when intravascular injection emboli are suspected.Due to its good dispersive properties,polymethyl methacrylate(PMMA)was used as the test filler.The main purpose of this study was to observe whether local massage as a simple remedial measure can promote the diffusion of filler and reduce the necrosis rate for intra-arterial embolism.Methods:Rabbit ears with the central ear artery(CEA)main trunk totally or segmentally obstructed 5 min after PMMA injection were studied.In order to simulate the massage effect of the fingers,the massage group was treated with a small beauty massage bar with a fixed vibration frequency along the direction of the blood flow.CEA blood flow and skin lesions were also analyzed.Results:The baseline data were similar between the control and massage groups.Compared to the control group,the recanalization rate of the CEA trunk in the treatment group increased significantly after massage.However,there was no significant difference in the visible rate of transparent embolus on the 1st day after treatment,nor in the necrosis degree or area of soft tissue damage on the 7th day after treatment.Further analysis showed that massage tended to have a positive effect on segmentally obstructed cases at 5 min after injection but a negative effect on totally obstructed ears at 5 min.Conclusion:Local massage cannot reduce the complications of tissue necrosis after intra-arterial PMMA injection.Prevention is key to reducing complications.

GTO/PMMA复合材料的制备及其透明隔热性能的研究

为了减少太阳热辐射对人体的损害已经消耗了地球的大量资源,目前研究更加新型的环保热屏蔽材料势在必行。采用正交试验法研究了溶剂载体种类、分散剂类型、改性时间及球磨时间对铯钨青铜(GTO)在甲基丙烯酸甲酯(MMA)中分散稳定性的影响。进一步研究了不同比例GTO/PMMA复合材料对隔热效果的影响并分析了其隔热机理。采用扫描电镜(SEM)、紫外-可见-近红外分光光度计对样品的微观形貌及近红外吸收性能进行了表征,通过自制隔热装置对其隔热性能进行了评价。实验结果表明:溶剂载体选用对苯二甲酸二辛酯(DOTP)为最优,在分散剂KENT-1103作用下,球磨时间24 h、振荡分散时间为24 h的稳定性最好;结合SEM和透射光谱分析,PMMA-GTO复合材料的相容性好,PMMA-0.4 wt%GTO的样品可见光透过率为39.96%,近红外光阻隔率96.91%,雾度为8.92%,隔热温度10.1℃,综合性能最好。

AN EPOXY/(METHYL METHACRYLATE)INTERPENETRATING POLYMER NETWORK FOR NONLINEAR OPTICS

An interpenetrating polymer networks (IPN) consisting of an epoxy-based polymer network and a polymethyl methacrylate network were synthesized and characterized. The IPN showed only one T-g, and hence a homogeneous-phase morphology was suggested. The second-order nonlinear optical coefficient (d(33)) of the IPN was measured to be 1.72 X 10(-7) esu. The study of NLO temporal stability at room temperature and elevated temperature (100 degrees C) indicated that the IPN exhibits a high stability in the dipole orientation due to the permanent entanglements of two component networks in the IPN system. Long-term stability of second harmonic coefficients was observed at room temperature for more than 1000 h.

PC/PMMA/GE复合材料的结构与性能

以石墨烯(GE)、聚碳酸酯(PC)及聚甲基丙烯酸甲酯(PMMA)为原料,制备了一系列PC/PMMA,PC/PMMA/GE复合材料。研究了PC,PMMA,GE不同配料比以及GE对PC/PMMA复合材料相结构、流变性能、力学性能的影响。结果表明:当PMMA质量分数达到40.00%时,PC/PMMA复合材料相结构从海岛型转变为共连续型。加入GE有利于细化PC/PMMA复合材料分散相粒径。增加PMMA含量和加入GE均能降低复合材料复数黏度。另外,GE在明显提高PC/PMMA复合材料断裂伸长率的同时,保证其拉伸强度基本不降低,这为高性能复合材料的设计与制备提供了一种思路。

STUDY ON FLUORESCENCE BEHAVIOUR OF EU^(3+) CONTAINING POLY(METHYL METHACRYLATE)

Fluorimetry has been used to characterize ionomers synthesized by copolymerization ofmethyl mehacrylate, methacrylic acid and europium methacrylate (EMA). Under excita-tion of UV light at 375 nm no seif-quenching was found in fluorescence of EMA containingionomers at 615nm within the concentration range of 1.6×10^(-2) to 11.49×10^(-2) mol%.This means that the distance between two Eu^(3+) ions is larger than 5nm. In the sameconcentration range seif-quenching took place in europium octanoate (EOA) containingpoly(methyl methacrylate) in which EOA was doped as an additive.

Surface Perfluoroalkyl Chains Segregation: A Tool for Reducing Calcium Deposits in Medical Grade Poly(Methyl Methacrylate)

Intraocular lenses can be manufactured from a wide variety of polymers, but due to the lost cost associated with the use of Poly (methyl methacrylate) (PMMA), it is still the preferred material used in the developing countries. However, a major drawback to its use is the build-up of calcium containing deposits that are formed on the intraocular lens over a period of time. In an attempt to hinder this deposition, surface modification of medical grade PMMA has been carried out using perfluoroalkyl chain (1,2,4-trifluoro-3-(C10F21CH2O)-7-(N,N)-dimethylaminoacridine) segregation. The segregation was explored using a 1% 1,2,4-trifluoro-3-(C10F21CH2O)-7-(N,N)-dimethyla-minoacridine in two methods: film casting and spin-coating, a thin film onto preformed PMMA discs. Both methods were compared against control PMMA to determine which method provided the best hindrance against calcium containing deposits when immersed in a simulated aqueous humour solution. Characterisation of the surface using scanning electron microscopy coupled with energy;dispersive x-ray analysis indicated that the surface segregation of perfluoroalkyl chains had hindered calcification in both methods. This pleminary research shows promising results of employing perfluoroalkyl chains in the surface segregation of biomaterials that can be employed in intraocular lenses.

POLYMERIZATION OF METHYL METHACRYLATE CHIRAL LIGANDS

Methyl methacrylate was anionically polymerized in the presence of chiral ligands,e.g.(+)-DDB and(-)-Sp.The polymers thus formed were optically inactive due to the instability of the helical chain for the less bulky ester group.Isotactic poly(methyl methacrylate)was given when(+)-DDB was used,whereas,a syndiotactic polymer was formed in the presence of(-)-Sp.Accordingly,two different propagation mechanisms were postulated.

纳米氧化锆对PMMA义齿基托性能影响的研究进展

近年来,材料学的发展促进了口腔修复学的进步,聚甲基丙烯酸甲酯(Polymethyl methacrylate,PMMA)由于具有易加工、成本低、生物相容性好等特点,是常用的义齿基托材料。然而在使用过程中发现PMMA存在着许多问题,如物理性能降低导致其易折断以及细菌粘附等,使用寿命较短,让其在临床上的使用变得局限,随着纳米颗粒材料的应用,多项研究发现加入纳米颗粒尤其是加入纳米氧化锆颗粒(nano zirconia,ZrNp)后的PMMA义齿基托的物理性能、抗菌性、抗老化性、生物相容性等得到了有效改善。因此本文就加入ZrNp对PMMA性能影响的研究进展进行综述,以期为口腔修复材料的临床选择及相关研究提供参考。

The Effect of Direct Gas Fluorination on Medical Grade Poly(methyl methacrylate)

Medical-grade poly(methyl methacrylate) (PMMA) is extensively employed in the fabrication of a variety of medical implants, including intraocular lenses (IOLs). However, a postoperative complication that leads to the failure of the implanted intraocular lenses has been recently identified. This process, termed calcification, occurs when calcium-containing deposits accumulate on the surface of the IOL. In this study direct gas fluorination was used to modify the surface of PMMA in an attempt to increase the service lifetime of the material in optical applications. PMMA discs exposed to a 20% fluorine/nitrogen gas mixture for 24 h were compared with untreated PMMA discs serving as control samples. Over time, both surface-fluorinated and untreated PMMA samples immersed in a simulated aqueous humour solution (SAHS) (pH 7.4, 35°C) were used to carry out in vitro studies. Attenuated total refractive Infrared spectroscopy (ATR-IR) Scanning electron microscopy (SEM), coupled with Energy dispersive X-ray analysis (EDX), showed that calcium-containing surface deposits were less abundant on surface-fluorinated PMMA compared with the control samples, indicating that the fluorinated surface was acting as a barrier to the deposits. Gravimetric analysis data showed that the decreased rate of diffusion compared with that of a control sample was due to the fluorinated surface.

Fabrication and Characterization of PMMA/MWCNTs Composite Materials

In order to improve the mechanical properties and thermal conductivity of polymethyl methacrylate(PMMA),multi-walled carbon nanotubes(MWCNTs)were used as reinforcement through in situ polymerization method to prepare PMMA/MWCNTs composites by changing the reaction time,polymerization temperature and the content of MWCNTs.The effects of different reaction conditions on the properties of the composites were studied.The results show that the mechanical properties,thermal/electrical conductivity and thermal stability of the composites are improved compared with the PMMA matrix.The tensile strength of the composites is increased by up to 24%.The bending strength of the composite material increases from20.41 to 68.04 MPa,and the maximum increase is 233%.Meanwhile,when the content of MWCNTs is 3 wt%,the thermal conductivity of the composite is 0.335 W/(m·K),which increases by138%,and the electrical conductivity is 3.94 S/m.The thermal stability of the composite has been significantly enhanced.The modified PMMA will be widely used in medicine,communications,electronics and other fields.

ABS高胶粉增韧PMMA的研究

研究了不同丙烯腈-丁二烯-苯乙烯共聚物(ABS)高胶粉含量对聚甲基丙烯酸甲酯(PMMA)结构与性能的影响,并以一种核-壳型共聚物硅/丙烯酸复合橡胶接枝(SAN)作为增容增韧的第三组分助剂,研究了其含量对ABS高胶粉/PMMA体系结构与性能的影响。结果表明,ABS高胶粉明显改善了PMMA的冲击强度和断裂伸长率,但降低了拉伸强度和弹性模量。随着ABS高胶粉含量增加,体系的复数黏度和储能模量均增加。加入硅/丙烯酸复合橡胶接枝SAN,ABS高胶粉/PMMA体系的拉伸强度稍有降低,缺口冲击强度有所增加,当硅/丙烯酸复合橡胶接枝SAN含量为4份时,体系缺口冲击强度为7.57 kJ/m^(2),比纯PMMA的缺口冲击强度(1.38 kJ/m^(2))提高了450%,从SEM照片也表征,此配方体系下的共混物有较好的相容性。

轻质化PMMA/玻纤光伏组件封装材料的研究及应用

目前光伏建筑一体化(BIPV)及各类轻质化光伏都偏向与轻和柔,但传统光伏组件封装使用的玻璃制成组件重量较重,诸如屋顶或者户外会存在一定的便携和安全问题。本文通过甲基丙烯酸甲酯(MMA)树脂涂覆玻纤交联的方法制备了轻质光伏组件封装材料,采用高温高湿老化机(双85)、耐紫外老化机(UV)、紫外分光光度计、万能材料试验机、耐溶剂测试分别表征了封装材料的耐老化、耐紫外、拉伸强度、弯曲模量、耐溶剂等性能。研究结果表明,在树脂含量60%,厚度0.3mm、引发剂含量1%时,经过300kW·h紫外辐照,双85测试3000h和耐溶剂测试后,封装材料透光率保持在89%,拉伸强度433MPa,水透1.2g/d·m^(2)。