Gilbert J L, Ney D S, Lautenschlager E P
Division of Biological Materials, Northwestern University, Chicago, Illinois 60611, USA.
Biomaterials. 1995 Sep;16(14):1043-55. doi: 10.1016/0142-9612(95)98900-y.
A novel material called 'self-reinforced composite poly(methyl methacrylate)' (SRC-PMMA) is described. This composite material consists of high strength, high ductility PMMA fibres embedded in a matrix of PMMA. Tensile tests, three-point flexural tests, fracture toughness tests and flexural fatigue tests were carried out on unidirectional continuous fibre SRC-PMMA materials. Commercial sheet PMMA and bone cement were also tested for comparison purposes. Two PMMA fibre sizes (40 and 120 microns diameters) with different mechanical properties were used to make the SRC-PMMA materials. The results of this study show that the tensile strength, tensile modulus and tensile strain-to-failure were significantly greater for the SRC-PMMA compared with commercial PMMA (P < 0.05). The flexural strength was not increased in the SRC-PMMA compared with PMMA alone but was greater than that in bone cement (P < 0.05). There were no differences in flexural modulus between any group. The flexural strain-to-failure (30-35% for SRC-PMMA) was about three times greater in SRC-PMMA compared with bone cement and PMMA. Fracture toughness of these SRC-PMMA materials was also significantly greater than PMMA and bone cement (P < 0.001). Fracture toughness values of 3.2 MPa m1/2 were found in the 40 microns SRC-PMMA compared with 2.3 MPa m1/2 for the 120 microns SRC-PMMA and 1.3 MPa m1/2 for PMMA and bone cement. The fatigue strength of both SRC-PMMA samples was significantly greater (P < 0.001) at 80 MPa (10(6) cycles) compared with bone cement and PMMA, both of which had fatigue strengths of about 18 MPa. Fatigue damage in the form of fibre splitting and fibre-matrix interface failure was observed in the SRC-PMMA samples while the PMMA and bone cement showed only smooth fractures. During cyclic fatigue testing, the ongoing damage processes were periodically monitored using several novel computer-based and analysis algorithms. The measured cyclic loads and displacements are used to determine the creep-fatigue displacements, the sample stiffness (or modulus) and the hysteresis damage energy as functions of the number of applied cycles associated with the fatigue loading. The hysteresis damage energy to failure was about 25 times greater in the SRC-PMMA samples (2000 J at 10(6) cycles) compared with bone cement or PMMA at the same number of cycles to failure (80 J) indicating much greater fatigue damage tolerance in these materials. This material, SRC-PMMA, may be applicable for use in several medical and/or dental applications.
本文描述了一种名为“自增强复合聚甲基丙烯酸甲酯”（SRC-PMMA）的新型材料。这种复合材料由高强度、高延展性的聚甲基丙烯酸甲酯纤维嵌入聚甲基丙烯酸甲酯基体中组成。对单向连续纤维SRC-PMMA材料进行了拉伸试验、三点弯曲试验、断裂韧性试验和弯曲疲劳试验。为作比较，还对商用聚甲基丙烯酸甲酯板材和骨水泥进行了测试。使用两种具有不同机械性能的聚甲基丙烯酸甲酯纤维尺寸（直径分别为40微米和120微米）来制备SRC-PMMA材料。本研究结果表明，与商用聚甲基丙烯酸甲酯相比，SRC-PMMA的拉伸强度、拉伸模量和拉伸断裂应变显著更高（P < 0.05）。与单独的聚甲基丙烯酸甲酯相比，SRC-PMMA的弯曲强度并未提高，但大于骨水泥的弯曲强度（P < 0.05）。任何组之间的弯曲模量均无差异。SRC-PMMA的弯曲断裂应变（30 - 35%）约为骨水泥和聚甲基丙烯酸甲酯的三倍。这些SRC-PMMA材料的断裂韧性也显著高于聚甲基丙烯酸甲酯和骨水泥（P < 0.001）。40微米SRC-PMMA的断裂韧性值为3.2 MPa·m1/2，而120微米SRC-PMMA的为2.3 MPa·m1/2，聚甲基丙烯酸甲酯和骨水泥的为1.3 MPa·m1/2。与骨水泥和聚甲基丙烯酸甲酯相比，两种SRC-PMMA样品在80 MPa（10^6次循环）时的疲劳强度均显著更高（P < 0.001），骨水泥和聚甲基丙烯酸甲酯的疲劳强度约为18 MPa。在SRC-PMMA样品中观察到纤维劈裂和纤维 - 基体界面失效形式的疲劳损伤，而聚甲基丙烯酸甲酯和骨水泥仅显示出光滑的断裂面。在循环疲劳试验过程中，使用几种基于计算机的新型分析算法定期监测正在进行的损伤过程。测量的循环载荷和位移用于确定蠕变 - 疲劳位移、样品刚度（或模量）以及作为与疲劳加载相关的施加循环次数函数的滞后损伤能量。与在相同失效循环次数（80 J）下的骨水泥或聚甲基丙烯酸甲酯相比，SRC-PMMA样品的失效滞后损伤能量约大25倍（在10^6次循环时为2000 J），表明这些材料具有更高的疲劳损伤耐受性。这种材料，即SRC-PMMA，可能适用于多种医学和/或牙科应用。
