Easy-Processable and Aging-Free All-Polymer Polysiloxane Composites

Abstract

Here, we report all-polymer polysiloxane composites that overcome the long-standing processing problems of silica-reinforced silicone rubbers. Polystyrene fillers are dispersed with styrene/dimethylsiloxane symmetric diblock and triblock copolymers that control the filler morphology, filler−matrix interactions, and filler−filler interactions. Surprisingly, the composites not only rival the traditional silica-reinforced polysiloxane in mechanical properties of cured materials but also have better processability and stability than the silica-filled compound before curing. Large amplitude oscillatory shear experiments demonstrate that the triblock copolymer addition strongly affects the rheological properties. We hypothesize that the bridges and entangled loops that were formed by the triblock copolymer can connect different PS domains to provide additional reinforcement. The aging effect that originates from PDMS chain adsorption on the filler particle surface is also avoided because of the thermodynamic repulsion between PS and PDMS phases.

3D Printable All-Polymer Epoxy Composites

“…In addition, the PEO midblock may also promote interaction between the PPE homopolymer with bridging and entangled loop conformations. 42,47 It also increases the content of staining by RuO 4 at the interface, which decreases the contrast between PPE and epoxy matrix.…”

“…In addition, the architecture of this triblock copolymer is designed to promote the interaction between different homopolymer domains as previously reported. 42 Table S1 summarizes the molecular characteristics of the various polymers as determined by size exclusion chromatography (SEC) and 1 H NMR data (Figures S1−S4). The molecular weight of the PS blocks in PS−PMMA and PS−PEO−PS is chosen to be larger than that of PPE, which can induce the swelling of the PS phase by PPE chains 43,44 and therefore promote compatibilization.…”

“…On the other hand, PEO is compatible with PMMA , and also has a stronger compatibility with the cured epoxy matrix than PMMA. ,, If the blend contains both PMMA and PEO and the content of PEO is less than PMMA, PEO disperses in the PMMA phase in the precured blend, and the negative impact of PEO may be limited. In addition, the architecture of this triblock copolymer is designed to promote the interaction between different homopolymer domains as previously reported Table S1 summarizes the molecular characteristics of the various polymers as determined by size exclusion chromatography (SEC) and 1 H NMR data (Figures S1–S4).…”

“…Thus, enthalpic considerations promote looped PEO coronae surrounding the PPE domains, which improves the dispersion of the PPE homopolymer, decreases the domain size, and therefore increases the viscosity and moduli of the blend. In addition, the PEO midblock may also promote interaction between the PPE homopolymer with bridging and entangled loop conformations. , It also increases the content of staining by RuO 4 at the interface, which decreases the contrast between PPE and epoxy matrix.…”

Standalone Block Copolymer Nanoballoons: Decoupling Self-Assembly from Implementation in Nanomanufacturing

“…Several previous works have described many such scenarios. − The vesicle is a particularly attractive structure because of its spherical enclosed space. With applications ranging from nanoreactors, biomedical devices, or potential filling materials in micromanufacturing, − the utility of this configuration is immense. However, conventional methods of vesicle formation have three primary limitations when considered from a nanomanufacturing perspective.…”