Co-reporter:Rui Liu, Zhenyu Yang, Yuxin Ni, Kaixuan Song, Kai Shen, Shaohui Lin, and Qinmin Pan
The Journal of Organic Chemistry August 4, 2017 Volume 82(Issue 15) pp:8023-8023
Publication Date(Web):July 12, 2017
DOI:10.1021/acs.joc.7b01248
Pd(II)/bipyridine-catalyzed conjugate addition of arylboronic acids to α,β-unsaturated carboxylic acids (including β,β-disubstituted acrylic acids) was developed and optimized, which provided a mild and convenient method for the highly challenging synthesis of β-quaternary carbons substituted carboxylic acids.
Co-reporter:Oluwasola Oribayo, Xianshe Feng, Garry L. Rempel, Qinmin Pan
Chemical Engineering Science 2017 Volume 160(Volume 160) pp:
Publication Date(Web):16 March 2017
DOI:10.1016/j.ces.2016.11.035
•FMSF-PDA-PFD and FMSF-PDA-ODA spill clean-up sorbents were successfully fabricated.•Hydrophobic molecule incorporation into pristine foam template was achieved.•Sorbents exhibits high sorption capacity and recovery for oil spill clean-up.•Excellent reusability and oil/water selectivity is displayed by sorbents.Oil spills have serious impact on the environment, and its effective remediation for environmental protection is of global significance. Thus, oil sorbents with interconnected microporous structures having superoleophilic and superhydrophobic properties have attracted significant interest as sorption materials for oil spill clean-ups. In this study, an approach inspired by the adhesive proteins secreted by mussels was used in modifying a commercially available formaldehyde-melamine-sodium bisulfite copolymer foam (FMSF) as a thiols and amine functionalized oil/solvent sorption material, resulting in significantly improved hydrophobicity and oleophilicity. Our strategy was based on facile conjugation of octadecylamine (ODA) and 1H,1H,2H,2H perfluorodecanethiol (PFD) molecules to polydopamine (PDA) adhered to the interior micropores of FMSF. The FMSF-PDA-PFD and FMSF-PDA-ODA foams so prepared showed excellent oil/water selectivity, without damaging its intrinsic 3-D porous structure. In oil and solvent sorption experiments using engine oil and chloroform, a very high oil sorption capacity (amounting to 84 and 152 times its own weight) was obtained respectively. They also showed excellent reusability, and the same good oil sorption capacity was retained after 50 cycles of sorption-squeezing steps. The absorbed oil in the foams could be removed and collected simply by squeezing, and the foams became ready for reuse. The superhydrophobic and superoleophilic foams exhibited a significant potential as an effective and low-cost oil absorbent for applications in large-scale oil-spill clean-ups and recovery.Download high-res image (278KB)Download full-size image
Co-reporter:Oluwasola Oribayo, Xianshe Feng, Garry L. Rempel, Qinmin Pan
Chemical Engineering Journal 2017 Volume 323(Volume 323) pp:
Publication Date(Web):1 September 2017
DOI:10.1016/j.cej.2017.04.054
•LPU-rGO-ODA foam spill clean-up sorbent was successfully fabricated.•Hydrophobic/oleophilic molecule incorporation into pristine LPU foam was achieved.•LPU-rGO-ODA exhibits high sorption capacity and recovery than commercial PP sorbent.•Excellent reusability and oil/water selectivity is displayed by LPU-rGO-ODA sorbent.Superhydrophobic and superoleophilic foam-like materials are attracting significant interest as promising absorbent for oil spill clean-up from water bodies. In this work, we report the synthesis of lignin based polyurethane (LPU) foam and its surface modification to form a superhydrophobic and superoleophilic sorbent, for use in spill clean-ups. The interior matrix of the LPU foam substrate was grafted with adhesive polydopamine-reduced graphene oxide (rGO) and octadecylamine (ODA), which reacted to transform the LPU foam skeleton to a superhydrophobic and superoleophilic 3-D structure. The resulting foam (designated as LPU-rGO-ODA) was shown to retain the interconnected porous structure, with a water contact angle of 152°. Spectroscopic and microscopic analyses were conducted to investigate the structure and morphology of the foam. Sorption experiments with crude oil, engine oil, kerosene and chloroform showed that the LPU-rGO-ODA foam was an excellent oil sorbent with a sorption capacity of 26–68 times its own weight, which was much greater than that of a commercial non-woven polypropylene sorbent. The LPU-rGO-ODA foam also exhibited a high selectivity to oil sorption and excellent reusability over repeated sorption-squeezing cycles. The absorbed oils in the sorbent could be removed and collected simply by squeezing the oil-laden sponge, and the foam sorbent became ready for reuse in next sorption cycle. As such, LPU-rGO-ODA foam is expected to be a promising oil sorbent for potential applications in oil-spill clean-ups.Download high-res image (210KB)Download full-size image
Co-reporter:Zhenyu Yang, Yuxin Ni, Rui Liu, Kaixuan Song, Shaohui Lin, Qinmin Pan
Tetrahedron Letters 2017 Volume 58, Issue 21(Issue 21) pp:
Publication Date(Web):24 May 2017
DOI:10.1016/j.tetlet.2017.04.035
•Highly reactive cationic Pd(II)-bpy was in situ generated in CH3NO2.•High yielded Pd(II)-catalytic addition to arylaldimines was optimized.•Air and moisture insensitive Pd(II)-catalysis was developed.•12 of 13 examples yielded >90% and showed high functional groups tolerance.An in situ generated cationic Pd(II)/bipyridine-catalyzed nucleophilic addition of arylboronic acids to N-sulfonyl arylaldimines was developed and optimized, and the reaction was proceeded highly efficiently and conveniently in CH3NO2. A series of arylboronic acids and N-sulfonyl arylaldimines were surveyed, and 12 of 13 examples gave 90∼96% yields.Download high-res image (36KB)Download full-size image
Co-reporter:Dizhu Yue;Oluwasola Oribayo;Garry L. Rempel
RSC Advances (2011-Present) 2017 vol. 7(Issue 48) pp:30334-30344
Publication Date(Web):2017/06/08
DOI:10.1039/C7RA03546B
The utilization of sustainable forestry waste resources in the production of polyurethane (PU) foam is a promising green alternative to the use of un-sustainable resources. In this work, we report the liquefaction of waste pine wood at different reaction temperatures and its application in synthesizing a melamine phosphate modified wood type polyurethane foam (designated as MWPU). Our strategy was to obtain liquefied pine-based polyol at an optimum reaction temperature and apply the polyol in synthesizing a flame retardant (MWPU) foam via the incorporation of a melamine phosphate (MP) filler. Spectroscopic and microscopic analyses were conducted to investigate the structure characteristics and the morphology of the liquefied waste pine wood polyol and the synthesized (MWPU) foam. An optimum liquefaction temperature of 160 °C was obtained and the glass transition temperature (Tg) for 10 wt% incorporated MP foam was 43.8 °C. The as-prepared (MWPU) foam showed higher glass transition temperature and storage modulus than pine wood based PU foam without MP. The MWPU foam withstood heating at 300 °C without significant degradation and also exhibited a higher thermal stability and limited oxygen index (LOI) value than pine wood based PU foam. These results provided an insight into the physical and structural properties of the as-prepared bio-based foam and paved the way toward preparing bio-based PU foam, which could further expand its potential applications.
Co-reporter:Jiamin Ji, Zhenyu Yang, Rui Liu, Yuxin Ni, Shaohui Lin, Qinmin Pan
Tetrahedron Letters 2016 Volume 57(Issue 25) pp:2723-2726
Publication Date(Web):22 June 2016
DOI:10.1016/j.tetlet.2016.05.022
•Pd-catalyzed conjugate addition of arylboronic acids to α,β-unsaturated amides.•The reaction was optimized and the substrates scope investigated.•Modest to excellent yields were given for different substrates.•The reaction is oxygen and moisture insensitive.The Pd(II)/bipyridine-catalyzed conjugate addition of arylboronic acid to α,β-unsaturated amides was developed and optimized, and the reaction was proceeded smoothly in air. A series of arylboronic acid and α,β-unsaturated amide substrates were surveyed, and modest to excellent yields were given.
Co-reporter:Yake Man;Luye Mu;Yun Wang;Shaohui Lin;Garry L. Rempel
Polymer Composites 2015 Volume 36( Issue 1) pp:8-16
Publication Date(Web):
DOI:10.1002/pc.22903
Rutile titanium dioxide (TiO2)/poly(methyl methacrylate-acrylic acid-butyl acrylate) nanocomposites were synthesized via seeded emulsion polymerization and characterized by Fourier transmission infrared, dynamic light scattering, X-ray diffraction, ultraviolet–visible (UV–vis) spectroscopy, scanning electron microscopy, transmission electron microscopy, and thermogravimetric analysis to study their UV-shielding property. The effects of the nanoseed types, surfactant concentrations, and functional monomer amounts on the polymerization conversion, particle size, emulsion stability, and morphologies of the resulting nanocomposites were investigated. The dependence of UV-shielding performance on the nanoparticle content and dispersion was also explored. The optimized results are obtained with 2 wt% of TiO2 nanoparticles addition, and the effectiveness of UV shielding is significantly increased by using the synthesized rutile nano-TiO2/polyacrylates, for which the nanocomposite coating with a thickness of 200 μm could block up to 99.99% of UV light (≤350 nm) as confirmed by UV–vis spectrometry. POLYM. COMPOS., 36:8–16, 2015. © 2014 Society of Plastics Engineers
Co-reporter:Bin Jiang;Tian Wei;Ting-Ting Zou;Gary L. Rempel;Qin-Ming Pan
Macromolecular Reaction Engineering 2015 Volume 9( Issue 5) pp:480-489
Publication Date(Web):
DOI:10.1002/mren.201500004
Metathetic degradation of polybutadiene (PB) in presence of a ruthenium catalyst is accomplished. Well-defined functionalized telechelic PB oligomers with a wide range of designed molecular weights (Mn) and polydispersity indexes (PDI) are achieved via the choice of chain transfer agents (CTAs), mole ratio of PB/CTA, mole ratio of PB/catalyst and the reaction time. Experiments are performed using Grubbs second generation catalyst (G2) in 1,2-dichloromethane at 30 °C. It has been demonstrated that the degradation performance can be controllably tuned by using selected monomers. Additionally, when mono-olefins are introduced, the Mn of metathesis products would be on order of a few hundred g mol−1 with narrow PDI (less than 1.50). The compositions and structures of the final product is determined using GC/MS analysis, which indicates that the butadiene repeating unit number of the telechelic oligomers, could be as low as two or even only one.
Co-reporter:Yubo Zhang, Jiamin Ji, Xiuliang Zhang, Shaohui Lin, Qinmin Pan, and Li Jia
Organic Letters 2014 Volume 16(Issue 8) pp:2130-2133
Publication Date(Web):March 28, 2014
DOI:10.1021/ol500549c
Cobalt-catalyzed cyclization of CO, imine, and epoxide has been developed. A convenient catalyst system composed of Co2(CO)8 and LiCl is identified, and the substrate scope has been explored. The reaction provides an efficient method for the synthesis of substituted 1,3-oxazinan-4-ones.
Co-reporter:Pinyo Wongthong, Charoen Nakason, Qinmin Pan, Garry L. Rempel, Suda Kiatkamjornwong
European Polymer Journal 2014 Volume 59() pp:144-155
Publication Date(Web):October 2014
DOI:10.1016/j.eurpolymj.2014.07.026
•Styrene-assisted grafting of MA onto DPNR was carried out by DMP technique.•Styrene and MA formed charge transfer complex for graft copolymerization.•Addition of styrene improved grafting efficiency and grafted MA content.•Styrene can enhance the rate of graft copolymerization.•Styrene is an effective comonomer for promoting grafting of MA onto DPNR.Grafting of maleic anhydride (MA) onto deproteinized natural rubber (DPNR) was carried out using a differential microemulsion polymerization technique. To improve the grafting efficiency (G.E) and reduce the gel content in the grafts, deproteinizing the NR latex was conducted before the grafting reaction and styrene (ST) comonomer was used to increase the G.E. The effects of initiator and monomer concentration, reaction temperature, reaction time, monomer addition rate, and ST/MA ratio on G.E and gel content were investigated. Kinetics of grafting reaction in either the presence or absence of ST was investigated. The results showed that introduction of copolymerizing styrene could significantly improve both the G.E and the grafting content. The G.E increased with increasing ST/MA ratio. The optimal grafting condition was initiator and MA concentrations of 7 wt% and 9 wt% of dried rubber content, ST/MA mole ratio of 4:1, and MA addition rate of 0.6 ml/min at 60 °C for 4 h. The addition of styrene to the grafting process enhances the graft copolymerization rate of MA grafting onto DPNR.Graphical abstract
Co-reporter:Mengwei Dai, Yun Wang, Maozhi Pan, Shaohui Lin, Garry L. Rempel, Qinmin Pan
Applied Surface Science 2014 Volume 289() pp:209-217
Publication Date(Web):15 January 2014
DOI:10.1016/j.apsusc.2013.10.136
Highlights
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Antireflection coating with high transmittance (over 99%) is synthesized.
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The refractive index of the coating prepared can be tailored by operation conditions.
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Transmittance in the short wavelength always poor in other studies is improved.
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The effect of surface microscopic roughness of coating on transmittance is revealed.
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A model is developed describing the effect of surface roughness on transmittance loss.
Co-reporter:Xingchen Lu;Gang Cao;Zhengfa Niu
Journal of Applied Polymer Science 2014 Volume 131( Issue 7) pp:
Publication Date(Web):
DOI:10.1002/app.40086
ABSTRACT
Poly(butyl acrylate-vinyl acetate-acrylic acid) based acrylic pressure sensitive adhesives (PSAs) were synthesized by solution polymerization for the fabrication of high performance pressure sensitive adhesive tapes. The synthesized PSAs have high shear strength and can be peeled off substrate without residues on the substrate at temperature up to 150°C. The PSAs synthesized in the present work are single-component crosslinked and they can be used directly once synthesized, which is convenient for real applications compared to commercial multi-component adhesives. The results demonstrated that the viscosity of the PSAs remained stable during prolonged storage. The effects of the preparation conditions such as initiator concentration, cross-linker amount, organosiloxane monomer amount and tackifier resin on the polymer properties, such as glass transition temperature (Tg), molecular weight (Mw), surface energy and shear modulus, were studied, and the dependence of the adhesive properties on the polymer properties were also investigated. Crosslinking reactions showed a great improvement in the shear strength at high temperature. The addition of tackifier resin made peel strength increase compared to original PSAs because of the improvement of the adhesion strength. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40086.
Co-reporter:Wenjing Zhang;Luye Mu;Yun Wang;Shaohui Lin
Journal of Applied Polymer Science 2014 Volume 131( Issue 7) pp:
Publication Date(Web):
DOI:10.1002/app.39991
ABSTRACT
Core–shell nanomaterials of poly(butyl acrylate)-poly(methyl methacrylate) were synthesized using a differential microemulsion polymerization method for being used as polyacrylate-based optical materials, which meet the requirement of anti-crease-whitening and proper mechanical strength. The effects of reaction temperature and surfactant amount on the particle sizes, as well as the effect of reaction temperature on the conversion and solid content were investigated to reveal the dependence of the application properties on the reaction conditions. The spherical morphology of core–shell nanoparticles was also studied via transmission electron microscopy. The resulting polymers with a core–shell monomer ratio of butyl acrylate/methyl methacrylate at 32/10 (vol/vol) demonstrated the optimal balanced properties in the anti-crease-whitening and mechanical property, confirmed by the visible light transmittance measurement and the dynamic analysis of the viscoelastic properties of the synthesized core–shell nanomaterials. The smaller the particle size, the better the transparency of the resulting polymer films. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39991.
Co-reporter:Liang Yuan, Yun Wang, Maozhi Pan, Garry L. Rempel, Qinmin Pan
European Polymer Journal 2013 Volume 49(Issue 1) pp:41-48
Publication Date(Web):January 2013
DOI:10.1016/j.eurpolymj.2012.10.005
Poly(methyl methacrylate) nanoparticles are synthesized via differential microemulsion polymerization, where the monomers in the reaction system are kept at very low concentrations by continuous differential addition. The effects of various reaction conditions, such as initiator, surfactants, reaction temperature and monomer loadings, on the particle size and molecular weight have been investigated. The effects of initiator and reaction temperature on latex particle numbers and polymer chain numbers within the particles were also investigated. It was observed that the dependence of particle size on reaction temperature and initiator concentration was non-monotonic. The optimized conditions were screened to prepare nanoparticles with the smallest size.Graphical abstractWith the increase in the initiator concentration, more active sites could be formed, therefore, the monomer amount that each active site could share becomes less and small particles would result; when initiator concentration is high enough, free radical number one particle could share would increase and then some dead polymer particles could be initiated more than one time resulting in a higher particle size.Highlights► To reduce particle size, an optimal temperature and initiator amount were found. ► The use of the co-surfactant does not show any benefit, it can be eliminated. ► Monomer/water ratio have effect on particle size if hydrophilic initiator used. ► Higher monomer/water ratio results in smaller particle if hydrophilic initiator used.
Co-reporter:Pinyo Wongthong, Charoen Nakason, Qinmin Pan, Garry L. Rempel, Suda Kiatkamjornwong
European Polymer Journal 2013 Volume 49(Issue 12) pp:4035-4046
Publication Date(Web):December 2013
DOI:10.1016/j.eurpolymj.2013.09.009
•Modification of DPNR via grafting with MA was prepared by DMP.•Protein removal of NR improved grafting efficiency and reduced gel content.•DPNR is a preferred substrate for grafting with MA.•Only one MA molecule was grafted from one isoprene unit.•DMP gives higher GE and lower gel content than conventional emulsion polymerization.Modification of natural rubber (NR) via grafting polymerization with maleic anhydride (MA) has received wide attention as it could improve the hydrophilicity of NR and extend its application to a wider application field. However, the grafting efficiency of MA onto NR in either the molten state or solution state is low and is accompanied with undesired high gel content in the grafts. In this work a novel technical route was developed in that a deproteinization operation was conducted before carrying out the grafting process and a differential microemulsion polymerization technique was applied for the grafting reaction. The effects of initiator and monomer concentration, reaction temperature, and reaction time on the grafting efficiency and gel fraction were investigated, and a comparison of the reaction performance was conducted for deproteinized NR (DPNR) and NR. The results indicated that the deproteinization operation could significantly improve the grafting efficiency and reduce the gel content, and a 29% yield of MA grafted onto the rubber backbone could be achieved at a condition of a DPNR:MA:initiator ratio of 85:9:6 (wt%) at 60 °C for 8 h.Graphical abstract
