OH‐ and NH<sub>2</sub>‐Terminated Hyperbranched Polysiloxanes: Controlled Synthesis, Characterization, Toughening, and Reinforcing Epoxy Resin

Excellent comprehensive dielectric properties (including dielectric constant and loss) are essential for electromechanical transducers. This work introduced a bimodal network composite with poly(dimethyl siloxane) (PDMS) and delaminated Ti3C2T x sheets (d-Ti3C2T x ) modified with hyperbranched polysiloxane (HPSi) (referred to as HPSi-d-Ti3C2T x ). Before the final cross-linking, HPSi-d-Ti3C2T x , trapped with short-chain PDMS (CS-PDMS) and long-chain PDMS (CL-PDMS), was pre-reacted, which formed a distinct bimodal network structure. d-Ti3C2T x /PDMS and HPSi-d-Ti3C2T x /PDMS composites with different filler loadings were prepared, and their percolation thresholds (f c) were 1.32 and 1.43 vol %, respectively The dielectric constant of 1.40 vol % HPSi-d-Ti3C2T x /PDMS is 23.7 at 102 Hz, which is 1.5 times that of 1.28 vol % d-Ti3C2T x /PDMS and 8.5 times that of pure PDMS. Meanwhile, the dielectric loss of HPSi-d-Ti3C2T x /PDMS composite is still relatively small (0.11 at 103 Hz). The origin of dielectric property optimization of the composite is attributed to the boundary capacitor model, the accumulated charges at the interfaces between the conductive filler and the insulating polymer matrix of the composite, and the distinct bimodal network structure.

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“…which is far below the theoretical value (4.5). 30,31 The above result provides evidence to the successful synthesis of HPSi.…”

Section: Methodssupporting

confidence: 53%

“…The chemical shifts at 1.23 ppm (2) and 0.62 (1) ppm represent (Si–O–CH 2 –C H 3 ) and (Si–C H 2 ), respectively. It can be concluded that the integration ratio of (Si–O–CH 2 –C H 3 ) to (Si–C H 2 ) is 1.1, which is far below the theoretical value (4.5). , The above result provides evidence to the successful synthesis of HPSi.…”

Section: Resultsmentioning

confidence: 70%

Enhanced Dielectric Properties of a Poly(dimethyl siloxane) Bimodal Network Percolative Composite with MXene

Lei

Wang

Gao

et al. 2020

ACS Appl. Mater. Interfaces

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“…The thermal behavior of the PPDA demulsifier was evaluated by thermogravimetric analysis (TGA), and the obtained TGA curve is shown in Figure . The weight loss of the sample in the 30–200 °C range was 7.44 % and is ascribed to the large amounts of amino groups in the molecular structure of the PPDA demulsifier . The amino group is a hydrophilic group that will combine with the water molecules in the air .…”

Section: Resultsmentioning

confidence: 99%

“…In the temperature range from 200 to 450 °C, the samples display a weight loss of nearly 80 % that may be caused by the breakage of the chemical bonds in the hyperbranched macromolecules. In this process, the small molecules escaping from the system are attributed to the decomposition of macromolecules . Finally, nearly 12 % of the remaining weight is ash content.…”

Section: Resultsmentioning

confidence: 99%

Treatment of Oily Wastewater Using a Hyperbranched Poly (amido amine) Demulsifier with 1,4‐Phenylene Diamine as Central Core

Zhang

Shen

et al. 2020

ChemistrySelect

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In the present study, a hyperbranched polymer demulsifier (PPDA) was synthesized by an improved “one‐pot” method with 1,4‐phenylene diamine as the central core, and ethylenediamine and methyl acrylate as the chain segments. NMR and Fourier transform infrared spectroscopy were used to confirm the molecular structure of the demulsifier, and thermogravimetric analysis was carried out to estimate its thermal stability. The effects of some important experimental parameters such as concentration, temperature and settling time on the demulsification performance were systematically studied. The results demonstrated that the light transmittance and oil removal ratio of oily wastewater reached to 47.9 % and 93.62 %, respectively, after demulsification with 20 mg.L−1 PPDA for 30 min at room temperature. With the same concentration and time at 60 °C, the light transmittance and oil removal ratio reached 57.0 % and 96.35 %, respectively. In addition, PPDA showed high salt tolerance over 10000 mg.L−1. The possible demulsification mechanism was examined by comparing the demulsification performance of different demulsifiers in diesel emulsion and oily wastewater, respectively. Furthermore, surface tension, interfacial tension, zeta potential and micrograph measurements provided convincing evidence for the possible demulsification mechanism. The surface tension reduction was 29.86 and 31.75 mN.m−1 at 25 °C and 60 °C, respectively. The corresponding critical micelle concentration was 4.17×10−7 and 5.50×10−7 mol.L−1, respectively. Additionally, the interfacial tension decreased from 15.70 to 6.96 mN.m−1 as the PPDA concentration increased from 20 mol. L−1 to 100 mol. L−1. This showed that PPDA easily absorbed at the interface and rapidly permeate into the interface film and then to broke the oil droplets. This work provides a new hyperbranched polymer demulsifier for the treatment of oily wastewater and is beneficial for understanding the demulsification mechanism.

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“…31 Meanwhile, silicon-containing modifiers are also constantly being studied, for that they may enhance the flame retardancy without sacrificing strength of epoxy resins. [32][33][34][35][36][37] However, the mechanical properties of epoxy resin may be compromised when too many modifiers are introduced for flame retardancy, which greatly reduces its use value. 15,17 Therefore, it is very necessary to find a way to get the flame retardancy and mechanical properties improved at the same time.…”

Section: Introductionmentioning

confidence: 99%

The P/Si synergistic effect enduing epoxy resin with improved flame retardancy and outstanding mechanical properties

Hou

Li²,

Wang

et al. 2022

High Performance Polymers

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The bisphenol F epoxy resin (DGEBF) reacted with 10-(2,5-Dihydroxyphenyl)-10H-9-oxa-10-phospha-phenantbrene-10-oxide (ODOPB) and phenyltrimethoxysilane (PTMS) to obtain a novel epoxy resin containing both phosphorus and silicon (EP-P/Si). EP-P/Si exhibited evidently improved flame retardancy, with a limited oxygen index value of 33.4% and UL-94 V-1 rating acquired. In cone calorimeter test, its peak heat release rate (PHRR), total heat release (THR), average effective heat of combustion (av-EHC), and total smoke production (TSP) were reduced by 36.0%, 19.5%,11.5%, and 7.2% compared with neat epoxy resin (EP), respectively, indicating that the P/Si synergistic effect not only improved the flame retardancy but also inhibited the smoke release. The flame retardancy mechanism was studied by analysis of char residue and pyrolysis behavior in gas phase. Scanning electron microscopy (SEM) results exhibited that EP-P/Si formed a dense and compact carbon layer acting as a barrier to inhibit further combustion. And the Fourier transform infrared (FTIR) spectra, laser Raman spectroscopy (LRS), and X-ray photoelectron spectroscopy (XPS) results indicated that it had good thermal stability. In addition, the pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) results suggested that the phosphorus-containing radicals (·PO2) that had quenching effect existed in the gas phase. While the flame retardancy got improved, EP-P/Si also exhibited excellent mechanical properties, with an improvement of 31.8%, 6.2%, and 369.7% in tensile strength, flexural strength, and impact strength compared with EP, respectively.

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OH‐ and NH₂‐Terminated Hyperbranched Polysiloxanes: Controlled Synthesis, Characterization, Toughening, and Reinforcing Epoxy Resin

Cited by 17 publications

References 60 publications

Enhanced Dielectric Properties of a Poly(dimethyl siloxane) Bimodal Network Percolative Composite with MXene

Enhanced Dielectric Properties of a Poly(dimethyl siloxane) Bimodal Network Percolative Composite with MXene

Treatment of Oily Wastewater Using a Hyperbranched Poly (amido amine) Demulsifier with 1,4‐Phenylene Diamine as Central Core

The P/Si synergistic effect enduing epoxy resin with improved flame retardancy and outstanding mechanical properties

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OH‐ and NH2‐Terminated Hyperbranched Polysiloxanes: Controlled Synthesis, Characterization, Toughening, and Reinforcing Epoxy Resin

Cited by 17 publications

References 60 publications

Enhanced Dielectric Properties of a Poly(dimethyl siloxane) Bimodal Network Percolative Composite with MXene

Enhanced Dielectric Properties of a Poly(dimethyl siloxane) Bimodal Network Percolative Composite with MXene

Treatment of Oily Wastewater Using a Hyperbranched Poly (amido amine) Demulsifier with 1,4‐Phenylene Diamine as Central Core

The P/Si synergistic effect enduing epoxy resin with improved flame retardancy and outstanding mechanical properties

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Product

Resources

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OH‐ and NH₂‐Terminated Hyperbranched Polysiloxanes: Controlled Synthesis, Characterization, Toughening, and Reinforcing Epoxy Resin