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Polymers
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Polymer-SiO₂ Composites
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Polymer-SiO₂ Composites

A special issue of Polymers (ISSN 2073-4360). This special issue belongs to the section "Polymer Composites and Nanocomposites".

Deadline for manuscript submissions: closed (30 June 2022) | Viewed by 23974

Special Issue Editor

Prof. Dr. Hyeon Mo Cho

E-Mail Website
Guest Editor
University College, Yonsei University, Incheon 21983, Republic of Korea
Interests: silicon chemistry; semiconductor manufacturing material
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Silica is a common, particularly attractive material around us. Silicon and oxygen are the two most abundant elements in the Earth’s crust, and their combination, silica, has been used in a variety of fields. The bond enthalpy of Si–O is much larger than that of the C–O bond, rendering the thermal stability of silica, and its larger bond angle and longer bond length provide bond flexibility. In addition, uncondensed OH groups (silanol) on the silica surface make it easy for silica to connect with other materials, such as organic compounds, metal oxides, and metals.

Through the hybridization of silica with suitable materials, polymer/SiO2 composites can be customized in many ways to meet the needs of new cutting-edge technologies. For example, investigations on their applications in sensors, photoactive materials, filters, anodes in lithium ion batteries, drug delivery systems, catalysts, and biocompatible materials have been conducted.

This Special Issue will cover but not be limited to the following aspects of polymer/SiO2 composite chemistry and technology: Novel preparation method for polymer/SiO2 composites; Novel micro- and macrostructural analysis of polymer/SiO2 composites; Novel chemical and physical properties of polymer/SiO2 composites; Applications of polymer/SiO2 composites.

Dr. Hyeon Mo Cho
Guest Editor

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Keywords

  • silica
  • SiO2
  • polymer
  • composite
  • sol-gel
  • organic-inorganic composite

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Published Papers (8 papers)

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Research

10 pages, 1672 KiB  
Article
Colloidal Crystal Films with Narrow Reflection Bands by Hot-Pressing of Polymer-Grafted Silica Particles
by Sawa Matsuura, Mami Obara, Naoto Iwata and Seiichi Furumi
Polymers 2022, 14(23), 5157; https://doi.org/10.3390/polym14235157 - 27 Nov 2022
Cited by 2 | Viewed by 1436
Abstract
Previous reports have shown that colloidal crystal (CC) films with visible Bragg reflection characteristics can be fabricated by the surface modification of monodisperse silica particles (SiPs) with poly(methyl methacrylate) (PMMA) chains, followed by hot-pressing at 150 °C. However, the reflection bands of the [...] Read more.
Previous reports have shown that colloidal crystal (CC) films with visible Bragg reflection characteristics can be fabricated by the surface modification of monodisperse silica particles (SiPs) with poly(methyl methacrylate) (PMMA) chains, followed by hot-pressing at 150 °C. However, the reflection bands of the CC films were very broad due to their relative disordering of SiPs. In this report, we attempted to fabricate the CC films using SiPs surface-modified with poly(n-octyl acrylate) (POA) chains by hot-pressing. When the cast films of POA-grafted SiPs were prepared by hot-pressing at 100 °C, the reflection bands were narrow rather than those of CC films of PMMA-grafted SiPs. This can be ascribed to easy disentanglement of POA chains during the hot-pressing process, thereby enabling the formation of well-ordered CC structures. Moreover, the reflection colors of CC films could be easily tuned by controlling the molecular weight of POA chains grafted on the SiP surface. Full article
(This article belongs to the Special Issue Polymer-SiO₂ Composites)
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>Schematic representation of synthesis of SiP-POA by the SI-ATRP.</p> Full article ">Figure 2
<p>TGA curves for SiP, SiP-Br, bulk POA (<b>A</b>) and three kinds of SiP-POAs with different molecular weights of POA chains (<b>B</b>).</p> Full article ">Figure 3
<p>Reflection characteristics of CC films of three kinds of SiP-POAs with different molecular weights of POA chains. (<b>A</b>) Reflection spectra of CC films of SiP-POA109k (<span class="html-italic">a</span>), SiP-POA191k (<span class="html-italic">b</span>) and SiP-POA278k (<span class="html-italic">c</span>) fabricated by hot-pressing at 100 °C. Insets represent the reflection images of CC films, and the white scale bars signify 5 mm. (<b>B</b>) SEM images of the CC film surfaces of SiP-POA109k (<span class="html-italic">a</span>), SiP-POA191k (<span class="html-italic">b</span>) and SiP-POA278k (<span class="html-italic">c</span>) observed from the top view. White scale bars signify 1 µm.</p> Full article ">Figure 4
<p>The relationship between the degrees of polymerization (<span class="html-italic">m</span>) of POA chains on the surface of SiPs and the maximum wavelengths of reflection bands (<span class="html-italic">λ</span>) of the CC films. The dashed line represents the linear regression line for the plots.</p> Full article ">
12 pages, 4858 KiB  
Article
Preparation and Corrosion Performance of PPy/Silane Film on AZ31 Magnesium Alloy via One-Step Cyclic Voltammetry
by Chuang Peng, Nana Cao, Ziheng Qi, Yongde Yan, Ruizhi Wu and Guixiang Wang
Polymers 2021, 13(18), 3148; https://doi.org/10.3390/polym13183148 - 17 Sep 2021
Cited by 4 | Viewed by 2103
Abstract
PPy/silane composite film on a magnesium alloy surface was prepared by one-step cycle voltammetry. The mixed solution of methanol and water was used as the hydrolysis solvent of a γ-(2,3-glycidoxypropyl) trimethoxysilane coupling agent (KH-560). The surface morphology of the PPy/silane film, the electro-polymerization [...] Read more.
PPy/silane composite film on a magnesium alloy surface was prepared by one-step cycle voltammetry. The mixed solution of methanol and water was used as the hydrolysis solvent of a γ-(2,3-glycidoxypropyl) trimethoxysilane coupling agent (KH-560). The surface morphology of the PPy/silane film, the electro-polymerization progress of KH-560 and PPy, the influence of the silane coupling agent and the corrosion behavior of the coated AZ31 Mg alloy were all investigated. The results indicated that the PPy/silane film on AZ31 Mg alloy via one-step cyclic voltammetry could provide better corrosion protection for an Mg alloy when the volume fraction of KH-560 in the hydrolysis solution was 15% and the time span of hydrolysis was 24 h with the 5.935 × 10−10 A cm−2 corrosion current density. Full article
(This article belongs to the Special Issue Polymer-SiO₂ Composites)
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Graphical abstract
Full article ">Figure 1
<p>The ATR-IR spectroscopy of the PPy/silane film.</p> Full article ">Figure 2
<p>The surface and cross section morphology after chemical or electrochemical reaction in sodium salicylate solution: (<b>a</b>) the surface morphology without an electric field; (<b>b</b>) the surface morphology with an electric field; (<b>c</b>) the section morphology without an electric field; (<b>d</b>) the section morphology with an electric field; and (<b>e</b>) EDS map analysis of the element N (when with an electric field).</p> Full article ">Figure 2 Cont.
<p>The surface and cross section morphology after chemical or electrochemical reaction in sodium salicylate solution: (<b>a</b>) the surface morphology without an electric field; (<b>b</b>) the surface morphology with an electric field; (<b>c</b>) the section morphology without an electric field; (<b>d</b>) the section morphology with an electric field; and (<b>e</b>) EDS map analysis of the element N (when with an electric field).</p> Full article ">Figure 3
<p>The surface and cross section morphology of the chemical and electrochemical reactions in the mix solution: (<b>a</b>) the surface morphology without an electric field; (<b>b</b>) the surface morphology with an electric field; (<b>c</b>) the section morphology without an electric field; (<b>d</b>) the section morphology with an electric field; (<b>e</b>) EDS map analysis of the element N (when with an electric field); and (<b>f</b>) EDS map analysis of the element Si (when with an electric field).</p> Full article ">Figure 4
<p>CV and the first cycle of different volume fractions of KH-560-prepared PPy/silane film on the AZ31 Mg alloy: (<b>a</b>) 5% KH-560; (<b>b</b>) 10% KH-560; (<b>c</b>) 15% KH-560; and (<b>d</b>) 20% KH-560.</p> Full article ">Figure 5
<p>The surface morphology of composite coating compared with different volume fractions of KH-560: (<b>a</b>) 5% KH-560; (<b>b</b>) 10% KH-560; (<b>c</b>) 15% KH-560; and (<b>d</b>) 20% KH-560.</p> Full article ">Figure 6
<p>EIS of PPy/silane film prepared at different concentrations of silane coupling agent in 3.5 wt% NaCl solution: (<b>a</b>) Nyquist plot; (<b>b</b>,<b>c</b>) bode plots; and (<b>d</b>) equivalent electric circuit.</p> Full article ">Figure 7
<p>The polarization curves of PPy/silane composite at different concentrations of silane coupling agent in 3.5 wt% NaCl solution.</p> Full article ">
18 pages, 1618 KiB  
Article
Thermal Stability of Nanosilica-Modified Poly(vinyl chloride)
by Jolanta Tomaszewska, Tomasz Sterzyński and Damian Walczak
Polymers 2021, 13(13), 2057; https://doi.org/10.3390/polym13132057 - 23 Jun 2021
Cited by 17 | Viewed by 3977
Abstract
The thermal stability of PVC with 1 wt % of spherical porous nanosilica, prepared by roll milling at processing time varied from 1 to 20 min, was investigated by means of visual color changes, Congo red, and thermogravimetric tests (TGA and DTG), as [...] Read more.
The thermal stability of PVC with 1 wt % of spherical porous nanosilica, prepared by roll milling at processing time varied from 1 to 20 min, was investigated by means of visual color changes, Congo red, and thermogravimetric tests (TGA and DTG), as a function of rolling time and composition of PVC matrix. The melt flow rate (MFR) measurements were realized to identify the degradation-induced changes of processing properties. A high level of gelation of the PVC matrix for all samples was verified by DSC (differential scanning calorimetry). It was found that the addition of porous nanosilica to absorb a certain volume of HCl, produced by dehydrochlorination reaction, leads to an improvement of thermal stability, an effect observed in a form of minor color changes of the samples, lower evolution of gas hydrogen chloride, and slight changes of the MFR value. It was demonstrated that the TGA measurements are not sufficiently sensible to detect the degradation of PVC at the processing conditions, i.e., at the temperature equal to 220 °C and below this temperature. Full article
(This article belongs to the Special Issue Polymer-SiO₂ Composites)
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>DSC thermograms for PVC<sub>R</sub> and PVC<sub>R</sub>/SiO<sub>2</sub> composites processed in rolling time of 1 min and 20 min: (1) PVC<sub>R</sub> 1 min; (2) PVC<sub>R</sub> 20 min; (3) PVC<sub>R</sub>/SiO<sub>2</sub> 1 min; (4) PVC<sub>R</sub>/SiO<sub>2</sub> 20 min.</p> Full article ">Figure 2
<p>The MFR of PVC and nanocomposites with SiO<sub>2</sub> as a function of rolling time: (1) PVC<sub>R</sub>/SiO<sub>2</sub>; (2) PVC<sub>R</sub>; (3) PVC<sub>C</sub>/SiO<sub>2</sub>, and (4) PVC<sub>C</sub>.</p> Full article ">Figure 3
<p>Color changes of PVC<sub>C</sub> and PVC<sub>R</sub> samples and PVC composites with SiO<sub>2</sub> as a function of the time of rolling progress.</p> Full article ">Figure 4
<p>The relative change, Δ<math display="inline"><semantics> <msubsup> <mi mathvariant="normal">L</mi> <mrow> <mi mathvariant="normal">S</mi> <mi mathvariant="normal">i</mi> <mi mathvariant="normal">O</mi> <msub> <mrow/> <mn>2</mn> </msub> </mrow> <mo>*</mo> </msubsup> </semantics></math> (%), values of SiO<sub>2</sub>-modified PVC vs. unmodified PVC, as a function of rolling time: (1) PVC<sub>C</sub>/SiO<sub>2</sub> vs. PVC<sub>C</sub>; (2) PVC<sub>R</sub>/SiO<sub>2</sub> vs. PVC<sub>R</sub>.</p> Full article ">Figure 5
<p>The relative change of ΔL*<sub>proc</sub> values of PVC and PVC/SiO<sub>2</sub> processed in various rolling times vs. PVC and PVC/SiO<sub>2</sub> taken after 1 min as a function of processing time: (1) PVC<sub>R</sub>/SiO<sub>2;</sub> (2) PVC<sub>R</sub>; (3) PVC<sub>C</sub>/SiO<sub>2</sub>; (4) PVC<sub>C</sub>.</p> Full article ">Figure 6
<p>Congo red thermal stability of PVC and nanocomposites with SiO<sub>2</sub> as a function of rolling time: (1) PVC<sub>R</sub>/SiO<sub>2</sub>; (2) PVC<sub>R</sub>; (3) PVC<sub>C</sub>/SiO<sub>2</sub>, and (4) PVC<sub>C</sub>.</p> Full article ">Figure 7
<p>The relative changes of thermal stability of SiO<sub>2</sub>-modified PVC vs. unmodified PVC, as a function of rolling time: (1) PVC<sub>C</sub>/SiO<sub>2</sub> vs. PVC<sub>C</sub>; (2) PVC<sub>R</sub>/SiO<sub>2</sub> vs. PVC<sub>R</sub>.</p> Full article ">Figure 8
<p>TGA/DTG thermograms of (<b>a</b>) PVC<sub>C</sub>; (<b>b</b>) PVC<sub>R</sub>; (<b>c</b>) PVC<sub>C</sub>/SiO<sub>2</sub>, and (<b>d</b>) PVC<sub>R</sub>/SiO<sub>2</sub> processed in 1 and 10 min of rolling time.</p> Full article ">
9 pages, 12836 KiB  
Article
Improvement of the Centrifugal Force in Gravity Driven Method for the Fabrication of Highly Ordered and Submillimeter-Thick Colloidal Crystal
by Ting-Hui Chen, Shuan-Yu Huang, Syuan-Yi Huang, Jia-De Lin, Bing-Yau Huang and Chie-Tong Kuo
Polymers 2021, 13(5), 692; https://doi.org/10.3390/polym13050692 - 25 Feb 2021
Cited by 3 | Viewed by 1891
Abstract
In this paper, we propose a modified gravity method by introducing centrifugal force to promote the stacking of silica particles and the order of formed colloidal crystals. In this method, a monodispersed silica colloidal solution is filled into empty cells and placed onto [...] Read more.
In this paper, we propose a modified gravity method by introducing centrifugal force to promote the stacking of silica particles and the order of formed colloidal crystals. In this method, a monodispersed silica colloidal solution is filled into empty cells and placed onto rotation arms that are designed to apply an external centrifugal force to the filled silica solution. When sample fabrication is in progress, silica particles are forced toward the edges of the cells. The number of defects in the colloidal crystal decreases and the structural order increases during this process. The highest reflectivity and structural order of a sample was obtained when the external centrifugal force was 18 G. Compared to the samples prepared using the conventional stacking method, samples fabricated with centrifugal force possess higher reflectivity and structural order. The reflectivity increases from 68% to 90%, with an increase in centrifugal force from 0 to 18 G. Full article
(This article belongs to the Special Issue Polymer-SiO₂ Composites)
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>Schematics of the experimental setup for depositing and stacking silica particles with different radii of rotation and rotational speeds. (<b>a</b>) The rotation arms; (<b>b</b>) composition of the cell; and <b>(c)</b> schematic diagram of silica particles during the process.</p> Full article ">Figure 2
<p>Variation in the reflectance values of samples stacked at different positions with rotational speeds of (<b>a</b>) 150 rpm; (<b>b</b>) 200 rpm; and (<b>c</b>) 250 rpm.</p> Full article ">Figure 3
<p>Reflectance values of samples stacked with a 30 wt % silica colloidal solution under different centrifugal forces.</p> Full article ">Figure 4
<p>SEM images of a structure stacked with a 30 wt % silica colloidal solution and under centrifugal forces of (<b>a</b>) 0; (<b>b</b>) 7; (<b>c</b>) 14; (<b>d</b>) 18; and (<b>e</b>) 21 G.</p> Full article ">Figure 5
<p>Reflectance values of samples stacked with a 50 wt % silica colloidal solution under different centrifugal forces.</p> Full article ">Figure 6
<p>Scanning electron microscope (SEM) images of structures stacked with a 50 wt % silica colloidal solution under centrifugal forces of (<b>a</b>) 0; (<b>b</b>) 7; (<b>c</b>) 14; (<b>d</b>) 18; and (<b>e</b>) 21 G.</p> Full article ">Figure 7
<p>Reflection spectra and SEM images of samples stacked at 0 and 18 G.</p> Full article ">
9 pages, 2595 KiB  
Article
Fast Curable Polysiloxane-Silphenylene Hybrimer with High Transparency and Refractive Index for Optical Applications
by Kyungkuk Koh and Honglae Sohn
Polymers 2021, 13(4), 515; https://doi.org/10.3390/polym13040515 - 9 Feb 2021
Cited by 5 | Viewed by 3084
Abstract
In this study, a fast curable polysiloxane-silphenylene hybrimer (PSH) was synthesized by the nonhydrolytic sol–gel condensation of phenyl-vinyl-oligosiloxane (PVO) and tris(dimethylhydrosilyl)benzene (TDMSB) under a Pt catalyst to investigate its optical property and thermal stability. The combination of PVO and tripod-type TDMSB results in [...] Read more.
In this study, a fast curable polysiloxane-silphenylene hybrimer (PSH) was synthesized by the nonhydrolytic sol–gel condensation of phenyl-vinyl-oligosiloxane (PVO) and tris(dimethylhydrosilyl)benzene (TDMSB) under a Pt catalyst to investigate its optical property and thermal stability. The combination of PVO and tripod-type TDMSB results in a hybrimer with a fast curing time of 30 min. The PSH exhibited a high refractive index of 1.60, 1.59, and 1.58 at 450, 520, and 635 nm, respectively. High transmittance of 97% at 450 nm was obtained. The PSH exhibited a very high transmittance of 97% before thermal aging. The high optical transmittance of the PSH was only slightly decreased by 0.5% of the transmittance at 180 °C for 72 h after thermal aging, and high transparency was maintained almost constant even after 72 h of high-temperature treatment. Full article
(This article belongs to the Special Issue Polymer-SiO₂ Composites)
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>FT-IR spectra of (<b>A</b>) Si-H and (<b>B</b>) vinyl vibrations before and after the curing of the PSH.</p> Full article ">Figure 2
<p>Graph for the hardness (Shore D) of the PSH according to the curing times (<b>A</b>) and TGA analysis of the PSH (<b>B</b>).</p> Full article ">Figure 3
<p>Cross-linker units such as phenyl [<a href="#B9-polymers-13-00515" class="html-bibr">9</a>], epoxy [<a href="#B8-polymers-13-00515" class="html-bibr">8</a>], zirconium [<a href="#B10-polymers-13-00515" class="html-bibr">10</a>], and silphenyl (this work) for the fabrication of polysiloxane hybrimers.</p> Full article ">Figure 4
<p>Hardness (Shore D) and curing times of OE-6630, polyphony hybrimer (PPH), PS, PES, PZH, and PSH. * indicates this work.</p> Full article ">Figure 5
<p>Refractive index of the PSH. The inset images represent the picture and cross-section SEM image of the PSH samples.</p> Full article ">Figure 6
<p>Refractive index and transmittance at 450 nm for the OE-6630 (Dow Corning), PPH, PS, PES, PZH, and PSH * indicates this work.</p> Full article ">Figure 7
<p>UV–Vis spectra of the silphenyl hybrimer (2 mm) before and after thermal aging at 180 °C for 72 h in air and the OE-6630 (Dow Corning, dotted orange line) (<b>A</b>). The photographs (middle) represent the pictures before and after the thermal aging test every 24 h. The change of transmittance of the PSH at 450 nm after thermal aging for 24, 48, and 72 h at 180 °C (<b>B</b>).</p> Full article ">Scheme 1
<p>Synthesis of (<b>A</b>) PVO by sol-gel condensation of VTMS and DPSD and (<b>B</b>) the polysiloxane-silphenylene hybrimer (PSH) by the hydrosilylation reaction of PVO and TDMSB.</p> Full article ">
14 pages, 4622 KiB  
Article
Comparison between SBR Compounds Filled with In-Situ and Ex-Situ Silanized Silica
by Pilar Bernal-Ortega, Rafal Anyszka, Yoshihiro Morishita, Raffaele di Ronza and Anke Blume
Polymers 2021, 13(2), 281; https://doi.org/10.3390/polym13020281 - 16 Jan 2021
Cited by 18 | Viewed by 2735
Abstract
The main advantages of the use of silica instead of carbon black in rubber compounds are based on the use of a silane coupling agent. The use of a coupling agent to modify the silica surface improves the compatibility between the silica and [...] Read more.
The main advantages of the use of silica instead of carbon black in rubber compounds are based on the use of a silane coupling agent. The use of a coupling agent to modify the silica surface improves the compatibility between the silica and the rubber. There are two different possibilities of modifying the silica surface by silane: ex-situ and in-situ. The present work studies the differences between these processes and how they affect the in-rubber properties of silica filled SBR compounds. Full article
(This article belongs to the Special Issue Polymer-SiO₂ Composites)
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>DSC freezing curve for pure cyclohexane.</p> Full article ">Figure 2
<p>(<b>a</b>) Fourier Transform Infrared Spectroscopy (FTIR) analysis of the of the unmodified and modified silicas with bis(triethoxysilylpropyl) disulfide (TESPD) (red line) and covering agent (blue line), TESPD (grey line) and covering agent (CA) (yellow line) and (<b>b</b>) thermogravimetric analysis (TGA) curves of the unmodified and modified silicas with TEPSD (red line) and covering agent (blue line).</p> Full article ">Figure 3
<p>Mooney viscosity of the studied samples.</p> Full article ">Figure 4
<p>(<b>a</b>) Uncured Payne effect and (<b>b</b>) ΔG’ of the studied samples.</p> Full article ">Figure 5
<p>Vulcanization curves of the studied samples.</p> Full article ">Figure 6
<p>(<b>a</b>) DSC freezing curves for the swollen compounds and (<b>b</b>) Freezing point depression of the compounds.</p> Full article ">Figure 7
<p>(<b>a</b>) Crosslink density measured by equilibrium swelling and (<b>b</b>) correlation between the crosslink density results obtained by freezing point depression and equilibrium swelling.</p> Full article ">Figure 8
<p>Dispergrader images of the SBR/silica compounds.</p> Full article ">Figure 9
<p>Stress-strain curves of the studied compounds.</p> Full article ">Figure 10
<p>(<b>a</b>) Reinforcement index of the studied samples and (<b>b</b>) Correlation between the reinforcement index and the Payne effect of the studied compounds.</p> Full article ">
13 pages, 13031 KiB  
Article
Effect of SiO2 Particles on the Relaxation Dynamics of Epoxidized Natural Rubber (ENR) in the Melt State by Time-Resolved Mechanical Spectroscopy
by Rossella Arrigo, Leno Mascia, Jane Clarke and Giulio Malucelli
Polymers 2021, 13(2), 276; https://doi.org/10.3390/polym13020276 - 15 Jan 2021
Cited by 9 | Viewed by 2159
Abstract
The rheological behavior of an epoxidized natural rubber (ENR) nanocomposite containing 10 wt.% of silica particles was examined by time-resolved mechanical spectroscopy (TRMS), exploiting the unique capability of this technique for monitoring the time-dependent characteristics of unstable polymer melts. The resulting storage modulus [...] Read more.
The rheological behavior of an epoxidized natural rubber (ENR) nanocomposite containing 10 wt.% of silica particles was examined by time-resolved mechanical spectroscopy (TRMS), exploiting the unique capability of this technique for monitoring the time-dependent characteristics of unstable polymer melts. The resulting storage modulus curve has revealed a progressive evolution of the elastic component of the composite, associated with slower relaxations of the ENR macromolecular chains. Two major events were identified and quantified: one is associated with the absorption of the epoxidized rubber macromolecules onto the silica surface, which imposes further restrictions on the motions of the chains within the polymer phase; the second is related to gelation and the subsequent changes in rheological behavior resulting from the simultaneous occurrence cross-linking and chain scission reactions within the ENR matrix. These were quantified using two parameters related to changes in the storage and loss modulus components. Full article
(This article belongs to the Special Issue Polymer-SiO₂ Composites)
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Figure 1
<p>Chemical formula of epoxidized natural rubber (ENR)25.</p> Full article ">Figure 2
<p>(<b>A</b>) Complex viscosity (full symbols) and storage modulus (empty symbols) and (<b>B</b>,<b>C</b>) SEM micrographs for ENR + SiO<sub>2</sub> composite at different magnifications.</p> Full article ">Figure 3
<p>“Weighted” relaxation spectra for ENR and ENR + SiO<sub>2</sub> composite.</p> Full article ">Figure 4
<p>Large amplitude oscillatory shear (LAOS) rheological data for (<b>A</b>) pristine ENR and (<b>B</b>) ENR + SiO<sub>2</sub> composite.</p> Full article ">Figure 5
<p>Weighted relaxation spectra for ENR + SiO<sub>2</sub> system subjected to subsequent frequency sweep measurements.</p> Full article ">Figure 6
<p>Time-resolved mechanical spectroscopy (TRMS) sweeps for ENR + SiO<sub>2</sub> at 180 °C: (<b>A</b>) storage modulus and (<b>B</b>) loss modulus.</p> Full article ">Figure 7
<p>Isochronal storage modulus for ENR + SiO<sub>2</sub>, collected at different times during TRMS tests.</p> Full article ">Figure 8
<p>(<b>A</b>) Gradient (<span class="html-italic">m</span>) of the G’ curves in the terminal region and (<b>B</b>) static modulus (<span class="html-italic">G</span>’|<span class="html-italic">ω</span> = 0) for the for the ENR + SiO<sub>2</sub> melt.</p> Full article ">Figure 9
<p>ATR-FTIR spectra for pristine (unfilled) ENR and ENR + SiO<sub>2</sub> composite before and after TRMS, in the range 1250–750 cm<sup>−1</sup>.</p> Full article ">Figure 10
<p>Multi-frequency plot for the variation of tan δ as a function of time for ENR + SiO<sub>2</sub> system.</p> Full article ">Figure 11
<p>Plots of β’ and β’’ as a function of thermal treatment time.</p> Full article ">
14 pages, 2651 KiB  
Article
The Investigation of the Silica-Reinforced Rubber Polymers with the Methoxy Type Silane Coupling Agents
by Sang Yoon Lee, Jung Soo Kim, Seung Ho Lim, Seong Hyun Jang, Dong Hyun Kim, No-Hyung Park, Jae Woong Jung and Jun Choi
Polymers 2020, 12(12), 3058; https://doi.org/10.3390/polym12123058 - 20 Dec 2020
Cited by 35 | Viewed by 5392
Abstract
The methoxy-type silane coupling agents were synthesized via the modification of the hydrolyzable group and characterized to investigate the change in properties of silica/rubber composites based on the different silane coupling agent structures and the masterbatch fabrication methods. The prepared methoxy-type silane coupling [...] Read more.
The methoxy-type silane coupling agents were synthesized via the modification of the hydrolyzable group and characterized to investigate the change in properties of silica/rubber composites based on the different silane coupling agent structures and the masterbatch fabrication methods. The prepared methoxy-type silane coupling agents exhibited higher reactivity towards hydrolysis compared to the conventional ethoxy-type one which led to the superior silanization to the silica filler surface modified for the reinforcement of styrene-butadiene rubber. The silica/rubber composites based on these methoxy-type silane coupling agents had the characteristics of more developed vulcanization and mechanical properties when fabricated as masterbatch products for tread materials of automobile tire surfaces. In particular, the dimethoxy-type silane coupling agent showed more enhanced rubber composite properties than the trimethoxy-type one, and the environmentally friendly wet masterbatch fabrication process was successfully optimized. The reactivity of the synthesized silane coupling agents toward hydrolysis was investigated by FITR spectroscopic analysis, and the mechanical properties of the prepared silica-reinforced rubber polymers were characterized using a moving die rheometer and a universal testing machine. Full article
(This article belongs to the Special Issue Polymer-SiO₂ Composites)
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<p>The chemical structure of the conventional silane coupling agents (SCA)s.</p> Full article ">Figure 2
<p>The chemical structure of the prepared SCAs.</p> Full article ">Figure 3
<p>FTIR spectra for 1 h hydrolysis reactions of the SCAs: (<b>a</b>) TESPD; (<b>b</b>) TMSPD; (<b>c</b>) DMSPD; and (<b>d</b>) spontaneous reactions of samples 5 and 6 during 10 days.</p> Full article ">Figure 4
<p>Gel permeation chromatography (GPC) data for methoxy-type SCAs after condensation side reactions.</p> Full article ">Figure 5
<p>FTIR spectra of the modified silica cake with the prepared SCAs.</p> Full article ">Figure 6
<p>The evaluation of remaining silica content in the wet masterbatch (WMB) sample with methoxy-type SCAs.</p> Full article ">Figure 7
<p>(<b>a</b>) The moving die rheometer (MDR) data for dry masterbatch (DMB) and WMB with SCAs. (<b>b</b>) The stress–strain curve of samples T-1–T-5.</p> Full article ">Figure 8
<p>The comparison of the DMB and WMB fabrication processes.</p> Full article ">Figure 9
<p>Schematic of the bonding of SCAs to a silica surface and the side reaction of the modified silica.</p> Full article ">
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