Influence of PMMA-Chain-End Tethered Polyhedral Oligomeric Silsesquioxanes on the Miscibility and Specific Interaction with Phenolic Blends

Abstract

Two different molecular weights of poly(methyl methacrylate) (PMMA) and PMMA containing polyhedral oligomeric silsesquioxane (PMMA-POSS) homopolymers have been prepared via the atom transfer radical polymerization (ATRP) technique. The miscibility and specific interaction behaviors of PMMA-POSS and PMMA with phenolic resin were investigated by differential scanning calorimetry and Fourier transform infrared spectroscopy (FTIR). FTIR results reveal that at least three competing equilibriums are present in the phenolic/PMMA-POSS blend: self-association of phenolic (hydroxyl-hydroxyl), hydroxyl-siloxane interassociation between phenolic and POSS, and hydroxyl-carbonyl interassociation between phenolic and PMMA. Among these blends, single and higher T g s of these phenolic/PMMA-POSS blends were observed than the corresponding phenolic/PMMA blends at same composition, revealing that a stronger interassociation interaction of hydroxyl-siloxane than the hydroxyl-carbonyl interaction. Furthermore, we also found the screening effect in phenolic/LPMMA-POSS blends that tends to significantly decrease the hydrogen bond formation of the hydroxyl-carbonyl interassociation.

Strong Screening Effect of Polyhedral Oligomeric Silsesquioxanes (POSS) Nanoparticles on Hydrogen Bonded Polymer Blends

“…Phenolic/PMMA systems are also miscible blends that have been studied extensively [24,25]. In a previous study, we determined a value of K A of 20 directly through a least-squares fitting procedure based on the fraction of hydrogen-bonded C=O groups measured experimentally in a binary phenolic/PMMA blend [25].…”

“…In a previous study, we determined a value of K A of 20 directly through a least-squares fitting procedure based on the fraction of hydrogen-bonded C=O groups measured experimentally in a binary phenolic/PMMA blend [25]. We also used atom transfer radical polymerization (ATRP) to prepare inorganic/organic polymer hybrids featuring polyhedral oligomeric silsesquioxane (POSS) moieties at the chain ends; we obtained well-defined PMMA and PMMA-POSS homopolymers with designed molecular weights (ca.…”

“…40,300 and 38,300 g/mol) and then blended them with phenolic resin. POSS is a new type of material capable of forming various nanocomposites [25]. POSS derivatives are interesting materials because one or more of their organic groups can be functionalized for polymerization, while their remaining unreactive groups can be designed to solubilize the inorganic core and control the interfacial interactions between the POSS units and the polymer matrix.…”

Poly(L-lactide) nanocomposites containing octaglycidylether polyhedral oligomeric silsesquioxane: Preparation, structure and properties

“…As an index of crystallinity, (I t -I 0 )/(I " -I 0 ) is used to define the relative light intensity, where I t and I 0 are the I value at time t c = t and 0, respectively, I " is the I value when it levels off. Figure 7 shows the typical (I t -I 0 )/(I " -I 0 ) changes with t c for PLLA/PLLA-OPOSS 30 films, where the starting, half, and ending times for overall PLLA/PLLA-OPOSS 30 crystallization [t c (S), t c (1/2), and t c (E), respectively] are defined. Figure 8 plotted the evaluated t c (S), t c (1/2), and t c (E) as a function of T c .…”

“…POSS molecules can be easily incorporated into polymer systems through blending, grafting or copolymerization [15,16]. For example, several polymers, such as HDPE [21], PP [22], epoxy [23][24][25][26], PMMA [27][28][29][30], PU [31,32], PET [33][34][35] and PC [36], have been blended with POSS. It has been reported that PLLA/POSS nanocomposites have enhanced crystallization rate, improved mechanical properties and accelerated hydrolytic degradation as compared with pristine PLLA [19].…”