Guang-Xin Chen

A synthetic strategy of coating multiwalled carbon nanotubes (MWCNTs) with cross-linkable octa-acrylate polyhedral oligomeric silsesquioxane (POSS) by combining Diels–Alder cycloadditions with atom transfer radical polymerization in a controlled manner is reported. First, the furfuryl-2-bromoisobutyrate is synthesized by an esterification reaction from 2-bromoisobutyryl bromide and furfuryl alcohol. Then, the MWCNT-based initiators of atom transfer radical polymerization (ATRP) are synthesized through a Diels–Alder reaction between MWCNTs and furfuryl-2-bromoisobutyrate with controlled grafted content. The MWCNT initiators are used to initiate the ATRP reaction of the octa-acrylate POSS on the MWCNT surface. Finally, a core–shell structure with a MWCNT at the center is obtained, with the thickness of the POSS shell adjusted through different initiators from 5, 10, to 15 nm. The POSS-coated MWCNT is compounded with polyvinylidene fluoride to obtain a kind of composite which has both high dielectric permittivity and low dielectric loss.

Epoxy-based high-k composites with low dielectric loss caused by reactive core-shell-structured carbon nanotube hybrids

Co-reporter:Hongfeng Tang, Guang-Xin Chen, Qifang Li

Materials Letters 2016 Volume 184() pp:143-147

Publication Date(Web):1 December 2016

DOI:10.1016/j.matlet.2016.08.036

●We report a method to synthesize core-shell CNTs hybrids contained epoxy groups.●The shell plays a role both in dielectric property improvement and filler dispersion.●We prepare a high-K epoxy/CNT composite with low dielectric loss.●The dielectric constant is about 152 and the dielectric loss is only 0.06 at 10 KHz.Polymer composites with a high dielectric constant (high-k) and low dielectric loss represent an important research topic for the rapid development of electronic industries. This paper reports on a type of high-k composite with low dielectric loss (dielectric constant is approximately 152, and dielectric loss is only 0.06 at 10 kHz) through a compounded epoxy resin with homemade core-shell-structured carbon nanotube (CNT) hybrids. The composite is prepared by in situ controlled free-radical copolymerization of divinylbenzene and glycidyl methacrylate on the surface of CNTs. The reactive shell contained epoxy groups that play a dual role in keeping the low dielectric loss of the composites and high dispersibility of the coated CNTs. The coated CNTs with proper thickness (about 30 nm) and epoxy value (0.011 mol/g) were selected to prepare the composites.

Facile strategy for preparation of core–shell-structured carbon nanotube–ionic liquid hybrids

Co-reporter:Ye Ren, Zheng Zhou, Guangzhong Yin, Guang-Xin Chen, Qifang Li

Materials Letters 2016 Volume 166() pp:133-136

Publication Date(Web):1 March 2016

DOI:10.1016/j.matlet.2015.12.052

•We report a method to prepare core–shell hybrids based on PIL-coated CNTs.•A thick PIL shell on CNTs surface was obtained by introducing divinylbenzene.•The PIL shell on CNTs can be adjusted from about 15 nm to 50 nm.•The dielectric property of hybrids was controlled with varied shell thicknesses.Functionalization of multi-walled carbon nanotubes (MWCNTs) with ionic liquids (IL) is an efficient method to improve the dispersibility and reactivity of MWCNTs. This work introduces a promising method for fabricating core–shell-structured MWCNTs–IL hybrids by using vinyl-benzyl IL as monomer for in situ controlled free-radical polymerization. Active radicals attached on the MWCNTs surface initiate the copolymerization of divinyl monomer and polymerizable IL. A polymer layer containing ionic species is formed and coated on the outer surface of MWCNTs. The resulting well-defined material shows excellent dielectric properties with different coating layer thicknesses.

Dielectric properties of poly(vinylidene fluoride) composites based on Bucky gels of carbon nanotubes with ionic liquids

Co-reporter:Guang-Xin Chen;Shicheng Zhang;Zheng Zhou;Qifang Li

Polymer Composites 2015 Volume 36( Issue 1) pp:94-101

Publication Date(Web):

DOI:10.1002/pc.22917

“Bucky gels” of carbon nanotubes were successfully prepared by grinding multi-walled carbon nanotubes (MWNTs) and ionic liquids (ILs) for several hours. A series of poly(vinylidene fluoride) (PVDF) composites with Bucky gels was obtained through simple melt compounding. The Raman spectrum showed significant interaction among the ILs, MWNTs, and PVDF. The dielectric behavior of the PVDF composites based on unmodified and IL-modified MWNTs was studied from 40 Hz to 30 MHz. The addition of ILs significantly enhanced the dielectric property of the PVDF/IL/MWNT ternary composites, which was much higher than that of the sum of PVDF/IL and PVDF/MWNT binary composites. The SEM results revealed that both MWNTs and ILs uniformly dispersed throughout the PVDF/IL/MWNT composites because of the strong interaction between them. The DSC and XRD results showed that the addition of ILs in the composites changed the crystallinity and crystal form of the PVDF. POLYM. COMPOS., 36:94–101, 2015. © 2014 Society of Plastics Engineers

Synthesis and Self-Assembly of o-Nitrobenzyl-Based Amphiphilic Hybrid Polymer with Light and pH Dual Response

Co-reporter:Shasha Li;Sha Ji;Zheng Zhou;Guangxin Chen;Qifang Li

Macromolecular Chemistry and Physics 2015 Volume 216( Issue 11) pp:1192-1200

Publication Date(Web):

DOI:10.1002/macp.201500044

High-k polymer/carbon nanotube composites based on a polyhedral oligomeric silsesquioxane matrix facilitated by ionic liquid

Co-reporter:Q. Li, P. Peng, G.-X. Chen and S. W. Yoon

Journal of Materials Chemistry A 2014 vol. 2(Issue 39) pp:8216-8221

Publication Date(Web):18 Aug 2014

DOI:10.1039/C4TC01199F

A composite was prepared in which octa-methylmethacrylate polyhedral oligomeric silsesquioxane (POSS) is polymerized as the matrix and carbon nanotube (CNT)-adsorbed 1-allyl-3-methylimidazolium hexafluorophosphate ionic liquid (IL) is used as the filler, which exhibited a high dielectric constant and low dielectric loss owing to a POSS coating layer formed in situ on the CNT surface between the vinyl groups of the IL and POSS.

Regulated Dielectric Loss of Polymer Composites from Coating Carbon Nanotubes with a Cross-Linked Silsesquioxane Shell through Free-Radical Polymerization

Co-reporter:Da Sun, Zheng Zhou, Guang-Xin Chen, and Qifang Li

ACS Applied Materials & Interfaces 2014 Volume 6(Issue 21) pp:18635

Publication Date(Web):October 22, 2014

DOI:10.1021/am503633t

We report a synthetic strategy for coating multiwalled carbon nanotubes (MWCNTs) with cross-linked octa-methacrylate-polyhedral oligomeric silsesquioxane (MA-POSS) by direct, in situ free-radical polymerization in a controlled manner. This strategy resulted in a core–shell structure with an MWCNT center. The shell thickness could be varied from ∼7 nm to 40 nm by choosing different initiators, solvents, and weight ratios of MWCNT and octa-MA-POSS. Coated MWCNT hybrids had controlled electrical performance depending on the coating layer thickness and were well-dispersed in the polymer matrix. POSS-coated MWCNTs were compounded with poly(vinylidene fluoride) to obtain a composite with high dielectric permittivity and low dielectric loss.Keywords: carbon nanotubes; composites; dielectric loss; free-radical polymerization

Alkali metal surfactant-facilitated formation of thick boron nitride layers on carbon nanotubes by dip-coating

Co-reporter:Xiang Li, Qifang Li, Guang-Xin Chen

Materials Letters 2014 Volume 134() pp:38-41

Publication Date(Web):1 November 2014

DOI:10.1016/j.matlet.2014.07.049

•We report a promoting process for traditional dip-coated boron nitride (BN) on CNT.•A thick BN shell coated on CNT was obtained by introducing alkali metal surfactant.•The BN shell on CNT can be adjusted from about 10 nm to 25 nm.•The electrical performance of hybrids was controlled with varied shell thicknesses.In this paper, we introduced sodium dodecyl benzene sulfonate (SDBS) to the impregnation solution to promote boron nitride (BN) formation on multi-walled carbon nanotubes (MWNTs) by dip-coating. BN coating formation on MWNTs can be greatly improved by SDBS. The resultant BN-coated MWNTs showed increased BN shell thickness, enhanced MWNT dispersion in the impregnation solution, and lower formation temperatures and times (at 1000 °C for 2 h under flowing nitrogen). The shell thickness of the MWNTs may be adjusted from about 10 nm to 25 nm. Electrical property testing also showed that increasing the shell thickness induces higher resistivity (from 0.12 Ω cm to 430 Ω cm) in the MWNTs.

Preparation and dielectric properties of poly(-caprolactone) compounded with bucky gels-like mixture

Co-reporter:Sang Won Yoon;Xianqian Ren

Journal of Applied Polymer Science 2014 Volume 131( Issue 10) pp:

Publication Date(Web):

DOI:10.1002/app.40231

Abstract

Poly(ε-caprolactone) (PCL) was melt compounded with “Bucky gels”-like mixture that prepared by grinding multiwalled carbon nanotubes (MWNTs) and ionic liquids (ILs). Raman spectrum showed the significant interaction between ILs and MWNTs. The dielectric behavior of PCL nanocomposites based on unmodified and IL-modified MWNTs was studied from 40 Hz to 30 MHz. The addition of ILs significantly enhanced the dielectric property of PCL/IL/MWNT ternary nanocomposites, which was much higher than that of the sum of PCL/IL with PCL/MWNT binary nanocomposites. The dielectric properties of PCL/IL/MWNT nanocomposites were mainly influenced by ILs in low frequency and were dominated by MWNTs in high frequency. SEM results revealed that a more uniform and fine dispersion of MWNTs were achieved throughout the PCL matrix because of ILs. The addition of ILs in nanocomposites changed the crystallinity of PCL. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40231.

Influence of polyhedral oligomeric silsesquioxanes (POSS) on blue light-emitting materials for OLED

Co-reporter:Tianfu Zhang, Jinze Wang, Manxi Zhou, Li Ma, Guangzhong Yin, Guangxin Chen, Qifang Li

Tetrahedron 2014 70(14) pp: 2478-2486

Publication Date(Web):

DOI:10.1016/j.tet.2013.11.082

Preparation of core−shell structured carbon nanotube-silsesquioxane hybrids by a direct free-radical reaction

Co-reporter:Da Sun, Qifang Li, Guang-Xin Chen

Materials Letters 2014 120() pp: 90-93

Publication Date(Web):

DOI:10.1016/j.matlet.2014.01.046

Hierarchical Assembly of Amphiphilic POSS-Cyclodextrin Molecules and Azobenzene End-Capped Polymers

Co-reporter:Jinze Li, Zheng Zhou, Li Ma, Guangxin Chen, and Qifang Li

Macromolecules 2014 Volume 47(Issue 16) pp:5739-5748

Publication Date(Web):August 14, 2014

DOI:10.1021/ma501100r

Stimuli-responsive polymers have been widely studied because of their potential use in nanocarriers and nanocontainers. In this study, a smart multistimuli responsive system was prepared through a light controlled supramolecular assembly. Mono cyclodextrin substituted isobutyl polyhedral oligomeric silsesquioxane (mCPOSS), an amphiphilic molecule, was synthesized by copper(I)-catalyzed azide–alkyne cycloaddition (CuAAC), while azobenzene end-capped poly(ethylene glycol)-b-poly(2-(dimethylamino)ethyl methacrylate) copolymer (PEG-b-PDMAEMA-azo, PPA), a biocompatible pH/temperature-responsive macromolecule, was synthesized by atom transfer radical polymerization and CuAAC. The self-assembly process of PPA and mCPOSS in aqueous solution was as followed: first, mCPOSS self-assembled into a nanosphere in aqueous solution because of its amphipathic property; then, the trans-azo end groups of the PPA interacted with the cyclodextrin cavities on the nanosphere, and complex micelles were formed by the supramolecular assembly between PPA and mCPOSS. In addition, the morphology of the micelles could be adjusted by the ratio of PPA and mCPOSS, the formation and the dissociation of the micelles could be controlled by visible and ultraviolet light, and the size of the micelles could be tuned by pH.

Gas Barrier and Biodegradable Properties of Poly(l-lactide) Nanocomposites Compounded with Polyhedral Oligomeric Silsesquioxane Grafted Organic Montmorillonite

Co-reporter:Qifang Li;Dan Bi

Journal of Polymers and the Environment 2014 Volume 22( Issue 4) pp:471-478

Publication Date(Web):2014/12/01

DOI:10.1007/s10924-014-0653-z

A novel organic montmorillonite (OMMT) was prepared by reacting the aminopropyllsobutyl polyhedral oligomeric silsesquioxane (POSS) with the OMMT that had already been modified by cationic surfactants. The layer spacing of OMMT increased from 1.68 to 3.43 nm after being intercalated by POSS. Poly(l-lactide) (PLLA) based nanocomposites with montmorillonites were produced by melt compounding. The PLLA nanocomposites with POSS modified OMMT were comprised of a random dispersion of intercalated/exfoliated aggregates of layered silicates throughout the PLLA matrix. The incorporation of POSS modified OMMT resulted in a significant increase in decomposition temperature for 5 % weight loss in comparison with the virgin PLLA. Gas permeation analysis showed that the increase of the montmorillonite concentration in the polymer matrix led to an expected decrease in permeation values. Gas barrier properties of the nanocomposites were compared with those predicted by phenomenological models such as the Nielsen model and Cussler model. Incorporation of the POSS on OMMT improved significantly mechanical properties of PLLA. The biodegradability of the neat PLLA and corresponding nanocomposite was studied under compost, and the rate of biodegradation of PLLA increased after nanocomposite preparation.

Synthesis of organic montmorillonite contained polyhedral oligomeric silsesquioxane and its nanocomposites with poly(l-lactide)

Co-reporter:Dan Bi;Da Sun;Jiali Qu;Zheng Zhou;Qifang Li

Polymer Engineering & Science 2014 Volume 54( Issue 11) pp:

Publication Date(Web):

DOI:10.1002/pen.23793

Three kinds of novel organic montmorillonites (OMMTs) were prepared by reacting the amino polyhedral oligomeric silsesquioxanes (POSSs) with the OMMTs that had already been modified by cationic surfactants. The layer spacing of OMMT increased from 1.68 to 3.81 nm after being intercalated by POSS. Poly(l-lactide) (PLLA) based nanocomposites with montmorillonites were produced by melt compounding. The PLLA nanocomposites with POSS modified OMMT were comprised of a random dispersion of intercalated/exfoliated aggregates of layered silicates throughout the PLLA matrix. The incorporation of POSS modified OMMT resulted in a significant increase in both crystallization temperature and decomposition temperature for 5% weight loss in comparison with the virgin PLLA. Gas Permeation Analysis showed that the increase of the montmorillonite concentration in the polymer matrix led to an expected decrease in permeation values. Gas barrier properties of the nanocomposites were compared with those predicted by phenomenological models such as the Nielsen model and Cussler model. POLYM. ENG. SCI., 54:2489–2496, 2014. © 2013 Society of Plastics Engineers

Synthesis of Photoresponsive Spiropyran-Based Hybrid Polymers and Controllable Light-Triggered Self-Assembly Study in Toluene

Co-reporter:Li Ma;Jinze Li;Dan Han;Haiping Geng;Guangxin Chen;Qifang Li

Macromolecular Chemistry and Physics 2013 Volume 214( Issue 6) pp:716-725

Publication Date(Web):

DOI:10.1002/macp.201200590

Abstract

A series of polyhedral oligomeric silsesquioxane end-capped poly(spiropyran-containing methacrylate) (POSS–PSPMA) polymers, a kind of photoresponsive hybrid polymer, are synthesized via atom transfer radical polymerization. It is proved that the molecular weight of POSS–PSPMA is sharply increased by raising the proportion of methanol or the concentration of the reactants. The self-assembly behavior of POSS–PSPMA is studied in toluene: under the control of UV and visible light, POSS–PSPMA can reversibly self-assemble into aggregates because the charged merocyanines (MC) form stacks. These MC stacks act as non-covalent crosslinking points and POSS shell guarantees the stability of the aggregates. This system has a broad potential use in nanocarriers, especially for encapsulating and releasing polar substances in the nonpolar solvents.

Fluorene/Carbazole Alternating Copolymers Tethered with Polyhedral Oligomeric Silsesquioxanes: Synthesis, Characterization, and Electroluminescent Properties

Co-reporter:Nana Xie;Jinze Wang;Zhilong Guo;Guangxin Chen;Qifang Li

Macromolecular Chemistry and Physics 2013 Volume 214( Issue 15) pp:1710-1723

Publication Date(Web):

DOI:10.1002/macp.201300290

RETRACTED: Polystyrene-b-poly(ethylene oxide) block copolymer thin films as templates for carbon nanotube dispersion

Co-reporter:Jing Wang, Fang Li, Qifang Li, Jianli Sun, Guang-Xin Chen

Thin Solid Films 2013 Volume 536() pp:191-195

Publication Date(Web):1 June 2013

DOI:10.1016/j.tsf.2013.04.002

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been retracted at the request of the corresponding authors and the Editor-in-Chief. The article is largely a duplication of a paper that has already been published in RSC Advances 2 (2012), pages 6637-6644; http://dx.doi.org/10.1039/C2RA20250F. One of the conditions of submission of a manuscript for publication is that the author declares explicitly that the paper has not been published yet or is not under consideration for publication elsewhere. As such, this article violated the guidelines.

A Strategy To Functionalize the Carbon Nanotubes and the Nanocomposites Based on Poly(l-lactide)

Co-reporter:Yihui Xu, Qifang Li, Da Sun, Wenjing Zhang, and Guang-Xin Chen

Industrial & Engineering Chemistry Research 2012 Volume 51(Issue 42) pp:13648-13654

Publication Date(Web):September 27, 2012

DOI:10.1021/ie300989w

A strategy to achieve balanced properties using functionalized carbon nanotubes has been investigated, and its nanocomposite exhibited good performance in mechanical and electrical properties. Polybutyl acrylate (PBA) has been utilized to functionalize multiwalled carbon nanotubes (MWNTs) by in situ atom transfer radical polymerization, resulting in a shell of molecular weight controlled on MWNTs (MWNT-PBA). Poly(l-lactide) (PLLA), which has been pitched on acting as the matrix of the polymers that are compatible with PBA such as poly(methyl methacrylate) (PMMA) and poly(vinylidene fluoride) (PVDF). A series of PLLA/MWNT-PBA nanocomposites were prepared by solution blending. Morphology, mechanical properties, and electrical properties have been tested, and the results showed that the volume electrical resistance of PLLA/MWNT-PBA nanocomposites decreased by 10 orders of magnitude as the content of MWNTs arrived at its percolation threshold, which is just 1.51 wt %, while the elastic modulus had increased 94.7%, compared to neat PLLA when the content of MWNTs is 2.98 wt %. Optical microscope images exhibited the spherulite morphologies of the nanocomposites while differential scanning calorimetry (DSC) measures showed that the temperature of cold crystallization increased when the content of MWNT-PBA increased.

Selective Self-Assembly of Surface-Functionalized Fullerenes in PS-PEO on Different Substrates

Co-reporter:Jing Wang, Guang-Xin Chen, Jianli Sun, and Qifang Li

The Journal of Physical Chemistry B 2011 Volume 115(Issue 12) pp:2824-2830

Publication Date(Web):March 10, 2011

DOI:10.1021/jp111115x

Polystyrene-functionalized C60 (C60-PS) was synthesized by atom-transfer radical polymerization. The structure of the hybrid was characterized by gel permeation chromatography and thermal gravimetric analysis. The self-assembly of polystyrene-block-poly(ethylene oxide) (PS-PEO)/C60-PS film in annealing solvents was studied on a silicon wafer and at the air/water interface by transmission electron microscopy. The method is an easy route to produce arrays of ordered nanostructures. The addition of C60-PS has a great effect on the self-assembly of PS-PEO. Treating the film under solvent vapor can modulate the orientation and ordering of PS-PEO microdomains. The C60-PS enhanced the formation of lamellae microstructure, and the C60-PS entered the PS phase, expanding the scale of PS domains. Nevertheless, it becomes more complex when it refers to the self-assembly at the air/water interface under solvent vapor for a long time. The selectivity of solvent to the polymer chains plays an important role as the annealing time increases.

Thermal and Biodegradable Properties of Poly(l-lactide)/Poly(ε-Caprolactone) Compounded with Functionalized Organoclay

Co-reporter:Qifang Li;Jin-San Yoon

Journal of Polymers and the Environment 2011 Volume 19( Issue 1) pp:59-68

Publication Date(Web):2011 March

DOI:10.1007/s10924-010-0256-2

Poly(l-lactide) (PLLA)/Poly(ε-caprolactone) (PCL) blends were compounded with commercially available organoclay Cloisite 25A (C25A) and C25A functionalized with epoxy groups, respectively. Epoxy groups on the surface of C25A were introduced by treating C25A with (glycidoxypropyl)trimethoxy silane (GPS) to produce so called Functionalized Organoclay (F-C25A). The silicate layers of PLLA/PCL/F-C25A were exfoliated to a larger extent than PLLA/PCL/C25A. Incorporation of the epoxy groups on C25A improved significantly mechanical properties of PLLA/PCL/C25A. The larger amount of exfoliation of the silicate layers in PLLA/PCL/F-C25A as compared with that in PLLA/PCL/C25A was attributed to the increased interfacial interaction between the polyesters and the clay due to chemical reaction. Thermo gravimetric analysis revealed that the nanocomposites with exfoliated silicate layers were more thermally stable than those with intercalated silicate layers. The biodegradability of the neat PLLA/PCL and corresponding nanocomposite was studied under compost, and the rate of biodegradation of PLLA/PCL increased after nanocomposite preparation.

Properties and morphology of interpenetrating polymer networks based on poly(urethane-imide) and epoxy resin

Co-reporter:Jiangxuan Song;Gang Wu;Jianjun Shi;Yun Ding;Guangxin Chen

Macromolecular Research 2010 Volume 18( Issue 10) pp:944-950

Publication Date(Web):2010 October

DOI:10.1007/s13233-010-1009-8

Incorporating elastic polyurethane in epoxy resin (EP) can enhance the physico-chemical properties but deteriorate the thermal stability. Poly(urethane-imide) (PUI) with a high reactive function group (-NCO), which combines the advantages of polyurethane and polyimide, was synthesized to simultaneously improve the toughness and thermal stability of epoxy resin. EP/PUI composites were prepared based on epoxy resin and poly(urethaneimide) with 4,4-diaminodiphenylmethane as the curing agent using a simultaneous polymerization method. FTIR analysis confirmed the formation of EP-g-PUI interpenetrating polymer networks via a reaction between -NCO of poly(urethane-imide) and -OH of epoxy resin. The thermal stability and mechanical properties were examined by thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and stress-tensile method, respectively. Corresponding to the pure epoxy resin, which has three stage thermal decomposition, the resulting PUI/EP composite exhibits only one stage and has a much higher initial decomposition temperature (323.8°C) than that (189.8°C) of the epoxy resin. Moreover, the EP/PUI composite has a higher glass transition temperature, tensile strength and breaking elongation when 30 phr PUI was added. With increasing PUI content to 70 phr, the breaking elongation was 213 times higher than that of the neat epoxy resin. The morphology of these composites was also investigated further by scanning electronic microscopy (SEM) and transmission electron microscopy (TEM). The results showed that a grafted interpenetrating polymer network was formed.

Synthesis of polyhedral oligomeric silsesquioxane-modified organic montmorillonites and their nanocomposites with poly(l-lactide)

Co-reporter:Dan Bi, Qifang Li, Guang-Xin Chen

Applied Clay Science (January 2014) Volume 87() pp:

Publication Date(Web):1 January 2014

DOI:10.1016/j.clay.2013.11.019

•The novel clay was prepared by reacting POSS with the organic montmorillonite.•The layer spacing of POSS modified clay increased from 1.68 nm to 3.74 nm.•Poly(l-lactide)/POSS modified clay nanocomposite displayed a 31 °C increase in T5%.•Nanocomposite with 10 mass% clay showed a 61 % decrease in gas permeability.•Gas permeabilities of nanocomposites were predicted by phenomenological models.Novel montmorillonites (Mts) were prepared by reacting aminopolyhedral oligomeric silsesquioxane (POSS) with organic Mt (OMt). Poly(l-lactide) (PLLA)-based nanocomposites with Mt were produced by melt compounding. The effects of POSS modified OMt (POSS-OMt) on the gas transport, thermal properties, and morphology of PLLA were investigated. POSS in the interlayers of OMt exerted important effects on the properties of the clay polymer nanocomposites (CPN). XRD studies revealed that the layer spacing of OMt increased from 1.68 nm to 3.74 nm after intercalation with POSS. TEM findings indicated that the CPN consisted of a random dispersion of intercalated/exfoliated aggregates throughout the PLLA matrix. DSC results demonstrated that incorporation of 2 mass% POSS-OMt results in a significant increase in crystallization temperature. TGA studies further showed that the CPN prepared from POSS-OMt displays a 31.2 °C increase in decomposition temperature for 5% mass loss relative to virgin PLLA. Gas permeation analysis showed that increasing the Mt concentration in the polymer matrix leads to expected decreases in permeation values. The gas barrier properties of the CPN were comparable with those predicted by phenomenological models, such as those from Nielsen and Cussler.Download full-size image

High-k polymer/carbon nanotube composites based on a polyhedral oligomeric silsesquioxane matrix facilitated by ionic liquid

Co-reporter:Q. Li, P. Peng, G.-X. Chen and S. W. Yoon

Journal of Materials Chemistry A 2014 - vol. 2(Issue 39) pp:NaN8221-8221

Publication Date(Web):2014/08/18

DOI:10.1039/C4TC01199F