乙烯基酯/纳米复合材料系统的形态学研究工作在日立S4500 SEM 8千伏的工作电压。块面临来自每个材料的准备,然后超薄部分(63海里)收集使用钻石刀Reichert Ultracut E超微切片机。等离子体蚀刻用于优先将乙烯基酯矩阵和离开粘土粒子表面的骄傲坐着。后坚持SEM存根,一层薄薄的金/钯应用于考试前标本广达250 FEG SEM。gydF4y2Ba
2.3.3。能量色散x射线谱(EDS)gydF4y2Ba
VE /纳米复合材料的形态结构进一步检查使用Jeol地产6060 lv显微镜在操作8千伏的电压工作。层状硅酸盐之间的分散度和乙烯基酯纳米复合材料样品的矩阵是用能量色散谱(EDS)、反向散射电子的副产品电子束的标本。在业务通过扫描光束光栅显示所选样品的强度信息,地图(图片)分布的元素可以产生。gydF4y2Ba
蠕变试验是用以下参数:60 N负荷,25°C和60°C, 96小时期间。整洁的聚合物,2 wt。wt %, 4。%nanocomposite samples were investigated. The specimens were prepared as 20 mm × 20 mm × 6 mm. This size sample was used in order to compare it with different mechanical tests such as tensile, flexural, and nanoindentation that have been already applied on the same geometry sample [
6gydF4y2Ba]。每个样品的初始和最终株strain-time曲线的计算。gydF4y2Ba
整洁的聚合物的XRD值和相应的纳米复合材料中可以看到表gydF4y2Ba
1gydF4y2Ba和图gydF4y2Ba
1gydF4y2Ba。10 Cloisite代表20°表明0.443 nm基底的距离。在2 wt。%粘土loading, the angle was shifted toward a lower angle compared to Cloisite 10 A and showed 16.86° which indicated 0.525 nm, so the intercalation of the nanocomposite structure took place. The enhancement of the d-spacing of the layered silicate of 2 wt.% was 16% compared to the pristine clay. At 4 wt.%, the
2gydF4y2Ba
θgydF4y2Ba减少得多而整洁的粘土和2 wt。%和represents 13.84° which indicated an intercalated basal spacing of 0.640 nm. The enhancement of the interlayer spacing at 4 wt.% was about 45% compared to the d-spacing of base clay. This enhancement in d-spacing value at the 4 wt.% reinforced samples indicated that the nanocomposites structure was intercalated or partially well-dispersed. In addition, the increment of basal distance indicated a good dispersion level of the clay into the polymer matrix. After the addition of more clay (i.e., 5 wt.%), the
2gydF4y2Ba
θgydF4y2Ba值16.08°,代表0.551纳米层状硅酸盐间距的减少相比4 wt. %。减少5 d-spacing wt。%米ay be attributed to the high viscosity of the mixture where insufficient mixing might have taken place, so agglomeration layers were observed in the nanocomposite structure. A clear relationship between the gallery distance and the level of distribution of the layered silicate in the matrix is proved by the
2gydF4y2Ba
θgydF4y2Ba值。gydF4y2Ba
XRD结果从不同的粘土纳米复合材料的加载。gydF4y2Ba
样本数量gydF4y2Ba
2gydF4y2Ba
θgydF4y2Ba值gydF4y2Ba
层间的距离(nm)gydF4y2Ba
d-spacing改进gydF4y2Ba%gydF4y2Ba
Cloisite 10gydF4y2Ba
20.00gydF4y2Ba
0.443gydF4y2Ba
00.00gydF4y2Ba
乙烯基酯+ 2 wt。%粘土gydF4y2Ba
16.86gydF4y2Ba
0.525gydF4y2Ba
18.51gydF4y2Ba
乙烯基酯+ 4 wt。%粘土gydF4y2Ba
13.84gydF4y2Ba
0.639gydF4y2Ba
44.24gydF4y2Ba
乙烯基酯+ 5 wt。%粘土gydF4y2Ba
16.08gydF4y2Ba
0.551gydF4y2Ba
24.38gydF4y2Ba
XRD结果整洁的聚合物和相应的纳米复合材料。gydF4y2Ba
3.1.2。扫描电子显微镜(SEM)gydF4y2Ba
SEM图像如图gydF4y2Ba
2gydF4y2Ba说明清楚的层状硅酸盐通过乙烯基酯为每个加载的三个层次。由于乙烯基酯的区别和散射的粘土密度、大型聚合粒子可以很容易地说明了SEM。如下所选择的图像显示,最大的粘土附聚物的大小相似,所有三个样本,30到35微米大小。然而,他们的频率与每个大粘土体积分数增加,和它们之间的填入度较小的聚合。可以看出,2 wt。%粘土加载exhibits uniform distribution layers throughout the polymer sea. Likewise, the well-dispersed clay within the vinyl ester matrix and unpronounced aggregation of layered silicate took place at higher amounts of clay such as 4 wt.%. The SEM image of 5 wt.% clay loading provides a high number of stacked clay particles compared to those at 2–4 wt.%. These findings are correlated with the results provided by XRD curves.
图gydF4y2Ba
3gydF4y2Ba代表着公司不同分数的层状硅酸盐的乙烯基酯矩阵。是观察粘土在聚合物的掺入海相当与少量凝结的均匀层粘土加载水平更高。同时,发现粘土载荷的增强导致增加的粘土集聚归因于混合物的粘度。EDS代表了层状硅酸盐为白色点反映了硅元素。在2 wt。%粘土loading, the level of distribution of clay into the vinyl ester matrix was uniform and no agglomeration layers were observed at 55x magnification of EDS. By the presence of more clay (i.e., 4 wt.%), the nanocomposite structure exhibited a reasonable intercalation/exfoliation structure although the aggregation of a few layers was obtained. In addition, the incorporation of high amounts of clay such as 5 wt.% led to reducing the homogeneity and increasing the aggregation and the microvoids in the nanocomposite structure. These results explain the reduction in the d-spacing value as was calculated by XRD and confirmed the results by SEM.
图gydF4y2Ba
4gydF4y2Ba显示了TEM显微图2、4和5 wt。%nanocomposite samples at 50 nm, where the bright area corresponds to the matrix sea and the dark lines signify the stacked or individual silicate layers. Indications from the higher magnification images are that greater levels of exfoliation nanocomposites are achieved with lower nanoclay loading. At 2 wt.% clay loading, the TEM image exhibits uniform distribution of layered silicate throughout the vinyl ester matrix. An intercalated/exfoliated structure is observed at 4 wt.% clay loading, as seen in Figure
4gydF4y2Ba。层状硅酸盐显示的说法与几个聚合粘土层。在5 wt。%粘土loading, additional dark regions are observed which indicate the aggregation of silicate layers and insufficient dispersion. TEM images conclude that the particle lumps (agglomeration) are increased by the addition of more than 4 wt.% clay loading. This was attributed to the high viscosity of the mixture where the ability to mix the layered silicate and the polymer is restricted. It is acceptable that the higher the amount of clay loading mixed with the polymer, the less exfoliated and aggregated the nanocomposite structure [
25gydF4y2Ba,gydF4y2Ba
26gydF4y2Ba]。这些结果支持结果通过XRD, SEM, EDS。gydF4y2Ba
在这项研究中,落锤冲击测试,这是最常见的复合材料和纳米复合材料,进行了简洁的乙烯基酯和相应的纳米复合材料。不同的粘土浓度使用包括2,4,5 wt。%粘土加载。冲击试验是为了分析和评估公司的影响的层状硅酸盐聚合物矩阵。许多参数可以计算出这个测试,如最大力量(N)和能量吸收(J)时间的函数(ms)曲线。每组四个标本进行了测试和计算平均值见表gydF4y2Ba
2gydF4y2Ba。从表gydF4y2Ba
2gydF4y2Ba虽然高负载的数量,公司的影响层状硅酸盐的乙烯基酯矩阵是可观测和粘土的加入导致提高冲击性能。最大的力和能量吸收分别增加了42%和59.74%,4 wt。%粘土加载。改进的最大负载和能量粘土装载的数量成正比;然而,在大量的粘土等加载5 wt。%,force and energy absorption decreased compared to the 4 wt.% clay concentration, as seen in Figures
5gydF4y2Ba和gydF4y2Ba
6gydF4y2Ba。这些结果表明,增加nanofillers聚合物基质不仅增加输出产品的力量,而且也增加了韧性。gydF4y2Ba
从(gydF4y2Ba
2gydF4y2Ba)和(gydF4y2Ba
3gydF4y2Ba),纳米复合材料的孔隙率样本计算和显示在表gydF4y2Ba
3gydF4y2Ba。可以看出,空洞比例粘土含量成正比。最大孔隙体积wt 5点被发现。%粘土加载wh我chrepresented 9.03%. The voids percentage can conclude that the acceptable voids content regards that the impact properties in the existence parameters used are to be less than 6.5% volume. Otherwise, less interfacial interaction between the layered silicate and the polymer will take place. Also, it may be noted that the tortuous path of the clay layers when the interface between them took place played an important role in the distribution of the mechanical stress applied. As concluded by SEM, the distance between particles and clay volume has an inverse relationship where the distance is decreased by the addition of more clay. Thus, the tortuous path is increased and the crack propagation would take a longer path. This phenomenon explains the improvement of the impact properties at 4 wt.% compared to 2 wt.%. As a result, the intercalation system can provide better impact properties than the exfoliation system [
29日gydF4y2Ba]。gydF4y2Ba
孔隙率不同的纳米复合材料样品。gydF4y2Ba
样本gydF4y2Ba
空隙度(%)gydF4y2Ba
百分比(%)gydF4y2Ba
乙烯基酯+ 2 wt。%粘土gydF4y2Ba
2.45gydF4y2Ba
1.32gydF4y2Ba
乙烯基酯+ 4 wt。%粘土gydF4y2Ba
6.40gydF4y2Ba
5.06gydF4y2Ba
乙烯基酯+ 5 wt。%粘土gydF4y2Ba
9.03gydF4y2Ba
7.55gydF4y2Ba
在5 wt。%粘土loading, the impact properties were reduced which was ascribed to the presence of the aggregation layers where the stress concentration factor was high. When the stress concentration factor is high, the initiation of premature failure may happen. In addition, the microvoids have contradictory functions regarding the impact properties. Fewer amounts of microvoids will allow the yield shielding of the applied load to be presented. However, the high amount of microvoids (i.e., 5 wt.%) will reduce the interfacial interaction between the polymer and layered silicate, so premature failure will dominate. Although the reduction of impact properties at high loadings of clay was observed, still there was an improvement compared to neat vinyl ester. This study was in close agreement to the report conducted by Lin et al. [
30.gydF4y2Ba]。gydF4y2Ba
不同样品的冲击断口形状如图所示gydF4y2Ba
7gydF4y2Ba。可以看到,整洁的聚合物表现出脆性骨折时样本分散进行负载的影响。孔的直径了整洁的乙烯基酯的冲击力是近40毫米。在2 wt。%粘土loading, the nanocomposite samples showed better impact stability compared to neat polymer. The samples were not wholly fragmented upon impact force. The hole diameter of the 2 wt.% nanocomposite was less than neat polymer which presented about 30 mm. The best impact resistance was found at 4 wt.% clay loading where the samples showed only about a 25 mm hole. At 5 wt.% nanocomposites, the sample showed less stability upon the impact load compared to the 4 wt.% clay loading and exhibited about a 30–40 mm diameter hole.
分裂的特点(一)整洁的乙烯基酯,2 wt (b)纳米复合材料。%粘土加载,4 wt (c)纳米复合材料。%粘土加载,和(d)nanocomposites of 5 wt.% clay loading.
表gydF4y2Ba
4gydF4y2Ba总结了整洁的乙烯基酯的蠕变松弛行为和相应的纳米复合材料在25°C和60°C。25°C,纳米复合材料样品的弹性响应表现出更少的干扰剪切流,如图gydF4y2Ba
8gydF4y2Ba。从图可以看出,原始聚合物提出了更高的间隔时间和施加压力。曲线的初始部分称为“蠕变曲线”,剩下的行为被称为“放松的水平。“根据蠕变数据,压力减少粘土浓度水平成正比。的聚合物说明高应变相比,纳米复合材料样品的应变开始在23%而2 wt。wt %和4。%nanocomposites showed 17% and 14%, respectively. In addition, the strain of the neat polymer started to increase after 40 hours by 2%, which was attributed to the temperature. However, the nanocomposites were almost stable during the mechanical stress applied and the temperature. The enhancement of the creep properties depends on many reasons, such as the level of intercalation between the clay and polymer, the clay source, and the clay shape [
31日gydF4y2Ba]。粘土悬浮的显微结构的变化也可以帮助提高蠕变行为。此外,层状硅酸盐的存在有助于改善microphase分离,所以增强弹性的发生和减少应力松弛过程的观察。此外,层状硅酸盐限制聚合物链的运动有助于承受机械应力。gydF4y2Ba
应变的整洁的乙烯基酯和相应的纳米复合材料在蠕变试验在不同间隔时间和温度。gydF4y2Ba
样本gydF4y2Ba
初始应变(%)gydF4y2Ba
应变在40个小时(%)gydF4y2Ba
应变在60小时(%)gydF4y2Ba
压力在80小时(%)gydF4y2Ba
压力在95小时(%)gydF4y2Ba
25°CgydF4y2Ba
60°CgydF4y2Ba
25°CgydF4y2Ba
60°CgydF4y2Ba
25°CgydF4y2Ba
60°CgydF4y2Ba
25°CgydF4y2Ba
60°CgydF4y2Ba
25°CgydF4y2Ba
60°CgydF4y2Ba
整洁的乙烯基酯gydF4y2Ba
23gydF4y2Ba
17gydF4y2Ba
25gydF4y2Ba
21gydF4y2Ba
26gydF4y2Ba
22gydF4y2Ba
26gydF4y2Ba
22gydF4y2Ba
26.3gydF4y2Ba
22.5gydF4y2Ba
乙烯基酯+ 2 wt。%粘土gydF4y2Ba
17gydF4y2Ba
13gydF4y2Ba
17.2gydF4y2Ba
13.2gydF4y2Ba
17.3gydF4y2Ba
13.3gydF4y2Ba
17.5gydF4y2Ba
13.4gydF4y2Ba
18gydF4y2Ba
13.6gydF4y2Ba
乙烯基酯+ 4 wt。%粘土gydF4y2Ba
14gydF4y2Ba
12gydF4y2Ba
14.2gydF4y2Ba
12gydF4y2Ba
14.4gydF4y2Ba
12.1gydF4y2Ba
14.6gydF4y2Ba
12.2gydF4y2Ba
15gydF4y2Ba
12.4gydF4y2Ba
整洁的聚合物的蠕变松弛行为和相应的纳米复合材料在25°C。gydF4y2Ba
类似的测试之前的蠕变行为进行60°C,以评估的影响温度对整洁和纳米复合材料样品。表gydF4y2Ba
4gydF4y2Ba和图gydF4y2Ba
9gydF4y2Ba显示所选样本的蠕变松弛行为。在同一案件中为25°C,施加压力下的纳米复合材料表现出良好的稳定性。温度越高(即。,60°C) represents better creep behaviour of the nanocomposite samples compared to 25°C, which may be attributed to the thermodynamic barrier where the enthalpic gain is translated into entropic gain. Thus, enhancement of the conformational links between the layered silicate and polymer took place [
32gydF4y2Ba]。此外,乙烯基酯可能调整使自己陷入了一个更多的命令或结构紧凑导致更强的交联塑料在更高的温度。它可以看到整洁的乙烯基酯开始变形应变增大的17%,而2 wt。wt %和4。%粘土loading represented an initial deformation at 13% and 12%, respectively. The neat polymer showed less stability where the temperature affected the sample and led to increase the deformation by 20.5% at 40 hours. At 83 hours, the base vinyl ester started again to deform and the strain increased by 22%. However, the nanocomposites exhibited almost the same deformation level at the initial and end time.