PCL/POSS Nanocomposites: Effect of POSS Derivative and Preparation Method on Morphology and Properties

Abstract

The incorporation of polyhedral oligomeric silsesquioxanes (POSS) molecules as nanoparticles into polymers can provide improved physico-chemical properties. The enhancement depends on the extent of dispersion of the nanofiller, which is determined by the compatibility with the polymer that is by the POSS type, and the processing method. In this study, poly(ε-caprolactone)/POSS derivatives nanocomposites (PCL/POSS) were obtained via solution-casting and melt compounding. Two amino-derivatives containing different alkyl substituents, and ditelechelic POSS-containing hybrid PCL masterbatch were used as nanofillers. The effect of preparation method, POSS content and type on the morphology, thermal, mechanical, and surface properties of nanocomposites were studied. Morphological analysis evidenced the formation of POSS crystalline aggregates, self-assembled POSS molecules of submicrometer size dispersed in the polymer matrix. The best dispersion was achieved using the ditelechelic POSS-containing hybrid PCL masterbatch, and comparing the two amino-POSS derivatives, the one with longer alkyl chain of substituents exhibited better degree of dispersion independent of preparation method. DSC analysis showed the role of POSS derivatives as nucleating agents for PCL. The incorporation of POSS derivatives into the PCL matrix improved thermal stability. The preparation method, POSS type and content had influence on mechanical properties of nanocomposites. POSS nanoparticles enhanced the surface hydrophobicity of PCL.

Effect of Alkyl Chain Length in POSS Nanocage on Non-Isothermal Crystallization Behavior of PCL/Amino-POSS Nanocomposites

“…The DSC curves of the PCL/APIBPOSS nanocomposites, in addition to the exothermic peak corresponding to the PCL crystallization, exhibit another small exothermic transition in the temperature range 41–47 °C (inset of Figure 1b–d) that corresponds to the APIBPOSS crystal formation. As we previously reported [22], APIBPOSS crystallizes and agglomerates in PCL matrix due to the POSS–POSS interactions. Due to the amorphous nature of APIOPOSS, the DSC curves of PCL/APIOPOSS composites exhibit only the exothermic crystallization peak of PCL.…”

“…The decrease in crystallinity is not the expected behavior for APIBPOSS-based nanocomposites since the above results suggest that it acts as nucleating agent. The liquid APIOPOSS exhibits higher compatibility with PCL than the crystalline solid APIBPOSS, which was attributed to the more thermodynamically favorable interactions between PCL and APIOPOSS [22]. The better compatibility leads to better dispersion; hence, smaller size aggregates were found in the case of PCL/APIOPOSS blends.…”

“…Nanocomposites with 2, 5, and 10 wt % POSS were obtained via solution and casting method as described elsewhere [22]. Both PCL and POSS were first dissolved in chloroform separately.…”

“…The purpose of the present study is to ascertain the effect of the alkyl-chain length of the nonreactive organic substituents attached to the corner silicon atoms of two amine-functionalized POSS on crystallization behavior of PCL. Recently, we have reported the effect of the alkyl-chain length of these substituents attached to the corner silicon atoms of amino-derivative POSS on morphology, thermal, and mechanical properties of PCL/amino-POSS nanocomposites [22]. We found that the longer the alkyl chain, the better the extent of dispersion of POSS due to the greater compatibility with PCL chains.…”

Effects of Polyhedral Oligomeric Silsesquioxane (POSS) on Thermal and Mechanical Properties of Polysiloxane Foam

“…For instance, by comparing the effects of APIB-POSS and AEAPIB-POSS on polyurethane foam, Członka et al [ 21 ] showed that the content of the filling material has a great influence on the foam. Cobos et al [ 22 ] studied the effects of different types and contents of POSS on various properties of PCL-derived composites. Niemczyk et al [ 23 ] studied a new type of POSS and applied it to the flame retardant aspect of PP materials.…”