DYNAMIC-MECHANICAL ANALYSIS OF 2 CROSS-LINKED COPOLYMER SYSTEMS
DYNAMIC-MECHANICAL ANALYSIS OF 2 CROSS-LINKED COPOLYMER SYSTEMS
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DOI：
10.1016/0109-5641(94)90036-1
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发表时间：
1994-09-01
期刊：
影响因子：
5
通讯作者：
RUEGGEBERG, FA
中科院分区：
文献类型：
--
作者：
TAMARESELVY, K;RUEGGEBERG, FA
目标.本文研究了两种模型牙科修复共聚物的动态力学性能，以阐明侧基长度和交联剂的加入对其的影响。将两种不同的单甲基丙烯酸酯树脂[（甲基丙烯酸甲酯（MMA）或2-乙氧基乙基甲基丙烯酸酯（EEM）]加入到不同摩尔分数（0、5、10、20、40、60、80和100%）的双官能单体[三甘醇二甲基丙烯酸酯（TEGDMA）]中，得到两种不同的共聚物体系（TMMA和TEEM）。将条形试样热固化，并在固定频率（1 Hz）下测试其动态力学性能：弯曲储能模量和损耗因子。使用tan δ、相位角和损耗因子确定与峰相关的转变温度。一个标本的属性也检查了使用范围内的应用频率。低于Tg时，所有树脂体系具有相似的储能模量。侧基长度的增加降低了转变温度，并表现出更大的影响，温度变化比交联剂含量的变化。随着交联剂的增加，转变温度增加。归因于转变温度的值取决于所使用的分析方法：tan δ给出最高值，其次是相位角，损耗因子值最低。储能模量和损耗模量值及其比值随外加信号频率的增加而增加。损耗因子分析提供了亚Tg转变的最大解释。具有特定所需物理和机械性能的修复聚合物可以通过明智地选择单体结构以及通过交联剂的受控添加来实现。
Objectives. This research investigated the dynamic mechanical properties of two model dental restorative copolymers to elucidate the influence of pendent group length and addition of crosslinking agent.Methods. Two different monomethacrylate resins [(methyl methacrylate (MMA) or 2-ethoxyethylmethacrylate (EEM)] were added to Various molar fractions (0, 5, 10, 20, 40, 60, 80 and 100%) of a difunctional monomer [triethylene glycol dimethacrylate (TEGDMA)], resulting in two different copolymer systems (TMMA and TEEM). Bar-shaped specimens were heat-cured and tested for their dynamic mechanical properties at a fixed frequency (1 Hz): flexural storage modulus and loss factor. Transition temperatures associated with peaks were determined using tan delta, phase angle and loss factor. The properties of one specimen were also examined using a range of applied frequencies.Results. Below the Tg, all resin systems had similar storage moduli. An increase in pendent group length lowered transition temperatures and demonstrated greater influence on temperature changes than did a change in crosslinker content. With increasing crosslinker, the transition temperatures increased. The values ascribed to transition temperatures were dependent upon the analysis method used: tan delta gave highest values, followed by phase angle, with loss factor values the lowest. Storage and loss moduli values and their ratio increased with increasing frequency of applied signal. Loss factor analysis provided the most elucidation of sub-Tg transitions.Significance. Restorative polymers with specific desired physical and mechanical properties can be achieved by both judicious selection of monomer structure as well as by the controlled addition of the crosslinking agent.