Nanocomposites of poly(m‐xylene diamide) with polyhedral oligomeric silsesquioxane, montmorillonite, and their combination: Structure and properties

Abstract

In this work, nanocomposites of poly (m-xylene diamide) (MXD6) with dodecaphenyl polyhedral oligomeric silsesquioxane (POSS), montmorillonite (MMT) and their combination (MMT-POSS) were produced by meltcompounding and their structure-property relationships were established. The montmorillonite was found to be homogeneously dispersed affording intercalated disordered structures whilst the distribution and dispersion of the POSS was rather skewed with the presence of phase separated crystalline aggregates of up to several hundred nanometers. Significant differences in properties were observed depending on the type of nanoscale filler present in the nanocomposites. The montmorillonite provided some improvements in stiffness and dynamic response of MXD6. POSS on the other hand improved the ductility of MXD6 and had a plasticizing effect. It has been suggested that there might be a lubricating action at the interface inducing better molecular motion between polymer chains of MXD6. By combining MMT and POSS, the properties of the corresponding nanocomposites were found to be intermediate. The thermal stability of MXD6 was enhanced in the nanocomposites although a negative deviation from the theoretical model was observed when POSS was present in the nanocomposites. This observation underlies some antagonistic effects which have been attributed to the presence of catalytic benzene radicals during thermal degradation. POLYM. ENG.

Graphene nanoplatelet-reinforced semi-crystal poly(arylene ether nitrile) nanocomposites prepared by the twin-screw extrusion

“…However, the absolute value of DH c in the PEN/GN composite significantly decreases as GN loading increases, indicating that the existence of GN decreases the crystallization degree of the resulted semi-crystal PEN nanocom-posites. Similar phenomenon has been reported by Magniez et al [28] in the poly(m-xylene diamide)/dodecaphenyl polyhedral oligomeric silsesquioxane/montmorillonite systems. The authors thought that in the primary stages of crystallization, the polymer spherulites nucleate quicker in the presence of the nanoparticles and grow freely until most of the spherulite surfaces impinge on each other [28].…”

“…Similar phenomenon has been reported by Magniez et al [28] in the poly(m-xylene diamide)/dodecaphenyl polyhedral oligomeric silsesquioxane/montmorillonite systems. The authors thought that in the primary stages of crystallization, the polymer spherulites nucleate quicker in the presence of the nanoparticles and grow freely until most of the spherulite surfaces impinge on each other [28]. In the secondary stage of crystallization, however, the presence of nanoparticles might cause steric hindrance resulting in a lower crystallinity [28].…”

“…The authors thought that in the primary stages of crystallization, the polymer spherulites nucleate quicker in the presence of the nanoparticles and grow freely until most of the spherulite surfaces impinge on each other . In the secondary stage of crystallization, however, the presence of nanoparticles might cause steric hindrance resulting in a lower crystallinity . Biswas et al also thought that the crystallization of polymer chain from the melt phase might cause the concentration and aggregation of small sized GN particles to the outside of the crystalline regions whereas the large size particles are too large to be displaced by the process of crystallization to cause any degree of concentration and agglomeration.…”

Zinc Oxide PVDF Nano‐Composites–Tuning Interfaces toward Enhanced Mechanical Properties and UV Protection

“…[38] At the slowest cooling rates of 5 and 10 C min À1 , PVDF was found to crystallize much faster (by up to 40%) in the presence of the ZnO NPs, highlighting again the nucleating ability of the ZnO (Figure 4). [50] Increasing the ZnO loading into the PVDF to a content exceeding 10 vol% did not significantly increase the time of crystallization (and this is particularly prominent at the slowest cooling rates).…”

“…It is most probable that spherulite impingement and steric hindrance during the stages of crystallization occurred, effectively slowing down the crystallization as previously reported for other nanocomposite systems. [50]…”