Polybutylacrylate (PBA)/poly(methyl methacrylate) (PMMA) core-shell elastic particles (CSEP), whose rubbery core diameter ranged from 0.08 μm to 1.38μm, were synthesized by using conventional emulsion polymerization...Polybutylacrylate (PBA)/poly(methyl methacrylate) (PMMA) core-shell elastic particles (CSEP), whose rubbery core diameter ranged from 0.08 μm to 1.38μm, were synthesized by using conventional emulsion polymerization, multi-step emulsion polymerization, and soapless polymerization. Allyl methacylate (ALMA) and ethylene glycol dimethacrylate (EGDMA) were selected as crosslinking reagents for core polymerization. Methacrylic acid (MAA) was used as functional co-monomer with methyl methacrylate as shell component. The content of vinyl groups in PBA rubbery core increased with the amount of crosslinking reagents. The core-shell ratio affected great on the morphology of the complex particles. Furthermore, the amounts of carboxyl on the surface of core-shell particles, copolymerized with acrylic acid, were determined by potentiometric titration. Results showed that methylacrylic acid was distributed mostly on the surface of particles.展开更多
The aim of the study was to evaluate the effect of adding acrylamide monomer （AAm） on the characterization, flexural strength, flexural modulus and thermal degradation temperature of poly（methyl methacrylate） （P...The aim of the study was to evaluate the effect of adding acrylamide monomer （AAm） on the characterization, flexural strength, flexural modulus and thermal degradation temperature of poly（methyl methacrylate） （PMMA） denture-base resins. Specimens （n= 10） were fabricated from a conventional heat-activated QC-20 （Qc-） and a microwave heat-activated Acron MC （Ac-） PMMA resins. Powder/ liquid ratio followed the manufacturer＇s instructions for the control groups （Qc-c and Ac-c） and for the copolymer groups, the resins were prepared with 5% （-5）, 10% （- 10）, 15% （- 15） and 20% （-20） acrylamide contents, according to the molecular weight ratio, respectively. The flexural strength and flexural modulus were measured by a three-point bending test. The data obtained were statistically analyzed by Kruskal-Wallis test （a=O.05） to determine significant differences between the groups, The chemical structures of the resins were characterized by the nuclear magnetic resonance spectroscopy. Thermal stabilities were determined by thermogravimetric analysis （TGA） with a heating rate of 10 ~C.min-1 from 35 ~C to 600 ~C. Control groups from both acrylic resins showed the lowest flexural strength values. Qc-15 showed significant increase in the flexural strength when compared to Qc-c （P〈O.01）. Ac-10 and Ac-15 showed significance when compared to Ac-c （P〈O.01）. Acrylamide incorporation increased the elastic modulus in Qc-10, Qc-15 and Qc-20 when compared to Qc-c （P〈0.01）. Also significant increase was observed in Ac-10, Ac-15 and Ac-20 copolymer groups when compared to Ac-c （P〈0.01）. According to the 1H-nuclear magnetic resonance （NMR） results, acrylamide copolymerization was confirmed in the experimental groups. TGA results showed that the thermal stability of PMMA is increased by the insertion of AAm.展开更多
Cranial defects often occur due to trauma. The treatment of such defects is a challenge to the skill and knowledge of the practitioner. This article presents one such case, where a 15-year-old boy had suffered extensi...Cranial defects often occur due to trauma. The treatment of such defects is a challenge to the skill and knowledge of the practitioner. This article presents one such case, where a 15-year-old boy had suffered extensive loss of the right cranium following a road traffic accident. The patient required rehabilitation of the right fronto-temporal cranial anatomy and was managed using a custom made heat polymerized acrylic alloplastic implant.展开更多
环氧树脂(E-44)与α-甲基丙烯酸(MAA)、甲基丙烯酸甲酯(MMA)、二甲基二氯硅烷(DMS)接枝共聚得到有机硅、丙烯酸单体改性环氧树脂三元聚合物,并以乙二胺固化。通过红外光谱表征了三元聚合物的结构,通过热性能、拉伸强度和断裂伸长率测定...环氧树脂(E-44)与α-甲基丙烯酸(MAA)、甲基丙烯酸甲酯(MMA)、二甲基二氯硅烷(DMS)接枝共聚得到有机硅、丙烯酸单体改性环氧树脂三元聚合物,并以乙二胺固化。通过红外光谱表征了三元聚合物的结构,通过热性能、拉伸强度和断裂伸长率测定以及电镜分析,研究了有机硅含量等对材料性能的影响。结果表明,丙烯酸、有机硅被成功引进环氧树脂,随着DMS用量的增加,环氧固化物的耐热性逐渐提高。当有机硅质量分数达到7%时,固化物的拉伸强度、断裂伸长率和冲击强度均达到最大值,分别是61.2 MPa、10.8%和18.6 k J/m2。展开更多
文摘Polybutylacrylate (PBA)/poly(methyl methacrylate) (PMMA) core-shell elastic particles (CSEP), whose rubbery core diameter ranged from 0.08 μm to 1.38μm, were synthesized by using conventional emulsion polymerization, multi-step emulsion polymerization, and soapless polymerization. Allyl methacylate (ALMA) and ethylene glycol dimethacrylate (EGDMA) were selected as crosslinking reagents for core polymerization. Methacrylic acid (MAA) was used as functional co-monomer with methyl methacrylate as shell component. The content of vinyl groups in PBA rubbery core increased with the amount of crosslinking reagents. The core-shell ratio affected great on the morphology of the complex particles. Furthermore, the amounts of carboxyl on the surface of core-shell particles, copolymerized with acrylic acid, were determined by potentiometric titration. Results showed that methylacrylic acid was distributed mostly on the surface of particles.
文摘The aim of the study was to evaluate the effect of adding acrylamide monomer （AAm） on the characterization, flexural strength, flexural modulus and thermal degradation temperature of poly（methyl methacrylate） （PMMA） denture-base resins. Specimens （n= 10） were fabricated from a conventional heat-activated QC-20 （Qc-） and a microwave heat-activated Acron MC （Ac-） PMMA resins. Powder/ liquid ratio followed the manufacturer＇s instructions for the control groups （Qc-c and Ac-c） and for the copolymer groups, the resins were prepared with 5% （-5）, 10% （- 10）, 15% （- 15） and 20% （-20） acrylamide contents, according to the molecular weight ratio, respectively. The flexural strength and flexural modulus were measured by a three-point bending test. The data obtained were statistically analyzed by Kruskal-Wallis test （a=O.05） to determine significant differences between the groups, The chemical structures of the resins were characterized by the nuclear magnetic resonance spectroscopy. Thermal stabilities were determined by thermogravimetric analysis （TGA） with a heating rate of 10 ~C.min-1 from 35 ~C to 600 ~C. Control groups from both acrylic resins showed the lowest flexural strength values. Qc-15 showed significant increase in the flexural strength when compared to Qc-c （P〈O.01）. Ac-10 and Ac-15 showed significance when compared to Ac-c （P〈O.01）. Acrylamide incorporation increased the elastic modulus in Qc-10, Qc-15 and Qc-20 when compared to Qc-c （P〈0.01）. Also significant increase was observed in Ac-10, Ac-15 and Ac-20 copolymer groups when compared to Ac-c （P〈0.01）. According to the 1H-nuclear magnetic resonance （NMR） results, acrylamide copolymerization was confirmed in the experimental groups. TGA results showed that the thermal stability of PMMA is increased by the insertion of AAm.
文摘Cranial defects often occur due to trauma. The treatment of such defects is a challenge to the skill and knowledge of the practitioner. This article presents one such case, where a 15-year-old boy had suffered extensive loss of the right cranium following a road traffic accident. The patient required rehabilitation of the right fronto-temporal cranial anatomy and was managed using a custom made heat polymerized acrylic alloplastic implant.
文摘环氧树脂(E-44)与α-甲基丙烯酸(MAA)、甲基丙烯酸甲酯(MMA)、二甲基二氯硅烷(DMS)接枝共聚得到有机硅、丙烯酸单体改性环氧树脂三元聚合物,并以乙二胺固化。通过红外光谱表征了三元聚合物的结构,通过热性能、拉伸强度和断裂伸长率测定以及电镜分析,研究了有机硅含量等对材料性能的影响。结果表明,丙烯酸、有机硅被成功引进环氧树脂,随着DMS用量的增加,环氧固化物的耐热性逐渐提高。当有机硅质量分数达到7%时,固化物的拉伸强度、断裂伸长率和冲击强度均达到最大值,分别是61.2 MPa、10.8%和18.6 k J/m2。
