材料期刊网

合成了一系列的PBA／PMMA核壳型复合弹性粒子,并用于增韧双酚A环氧树脂DEGMA／DDM体系。研究表明,适宜的PBA／PMMA核壳比是核壳型复合弹性粒子增韧环氧树脂的先决条件;添加合适核壳比的复合粒子能提高改性体系的冲击强度、剪切强度、降低固化体系的内应力。随着核壳粒子橡胶相尺寸的减小,改性体系的冲击强度逐渐增加,内应力降低,但对体系的剪切强度影响并不显著。在外力作用下观察到核壳粒子空穴化引起剪切屈服增韧。核壳粒子的形态由透射电镜观测(TEM),改性试样的断裂表面由扫描电镜观测(SEM)。改性体系中分散相的尺寸由预制结构的核壳复合粒子控制。

Polybutylacrylate(PBA) core-polymethylacrylate(PMMA) shell elastic particles(CSEP), whose rubbery core diameter ranged widely from 0.08 μm to 1.38 μm, were utilized as modifiers for DGEBA／DDM system. It is found that impact and shearing strength of epoxy resin is substantially enhanced by the addition of the core-shell elastic particles especially when the core-shell ratio is about 60／40. Impact and shearing strength attach maximums as the loading volume (LD) of CSEP about 10 phr. With the decrease of core sizes, the impact strength modified systems increases and the internal stress of modified systems decreases apparently, while shearing strength changes slightly. CSEP with a suitable cross-linking density of rubbery core by using EGDM／ALMA compound cross-linking agent shows more effectiveness on toughness. Results indicate that CSEP disperses in epoxy matrix well, and the morphologies of dispersed rubber domains are controlled perfectly by CSEP whose structure is designed previously.