2015 Volume 33 Issue 11

Poly(N,N-dimethylaminoethyl methacrylate) Grafted Poly(vinyl chloride)s Synthesized via ATRP Process and Their Membranes for Dye Separation
Li-feng Fang , Na-chuan Wang , Ming-yong Zhou , Bao-ku Zhu , Li-ping Zhu , Angelin Ebanezar John
2015, 33(11): 1491-1502  doi: 10.1007/s10118-015-1701-4
[Abstract](598) [FullText HTML] [PDF 0KB](0)
Abstract:
To functionalize poly(vinyl chloride) (PVC) for various applications, monomers containing tertiary amine group are incorporated into PVC via atom transfer radical polymerization (ATRP) initiated by the labile chlorines in their backbones. The kinetics of synthesis was carefully investigated, and it is proven that the grafting polymerization process can be effectively controlled by regulating the reaction time. The membranes are fabricated using PVC and copolymers by non-solvent induced phase separation (NIPS) process. The hydrophilicity and pore structure of copolymer membranes were enhanced as well, these membranes are endowed with positive charge. When PDMA% (i.e., the PDMA weight percentage in copolymer) is 31.1%, the flux and Victoria blue B rejection are 26.0 Lm-2h-1 (0.5 MPa) and 91.2%, respectively. Thus, the newly synthesized polymer is proven to be a promising material for dye separation with positive charges.
Surface-induced Morphologies of ABC Star Triblock Copolymer in Spherical Cavities
Wen-bo Jiang , Yong-yun Ji , Wen-chang Lang , Shi-ben Li , Xiang-hong Wang
2015, 33(11): 1503-1515  doi: 10.1007/s10118-015-1706-z
[Abstract](569) [FullText HTML] [PDF 0KB](0)
Abstract:
The morphologies and phase diagrams exhibited by symmetric ABC star triblock copolymer nanoparticles are investigated on the basis of real-space self-consistent field theory. The ABC star triblock copolymers were chosen to be tiling-forming with fixed polymer parameter and the spherical boundaries were modeled using the masking technique. We first study a number of examples where the ABC triblock copolymers confined in spherical cavities with neutral surface. Then, two types of spherical cavity distinct preferential surfaces are considered, including both A-block attractive and repulsive preferential surfaces. We aim at the effects due to various spherical cavity diameters and the degree of interactions between the polymer and the spherical surface. A variety of morphologies, such as ring-like structures, concentric sphere, and irregular cylinder, were identified in phase diagrams. The results show that both the degree of interactions and spherical diameters can influence the formation of morphologies so that ring-like structures and other novel structures could be obtained.
Thermo-sensitive Poly(DEGMMA-co-MEA) Microgels: Synthesis, Characterization and Interfacial Interaction with Adsorbed Protein Layer
Zhen-bing Li , Yan-hui Xiang , Xian-jing Zhou , Jing-jing Nie , Mao Peng , Bin-yang Du
2015, 33(11): 1516-1526  doi: 10.1007/s10118-015-1694-z
[Abstract](596) [FullText HTML] [PDF 0KB](0)
Abstract:
The novel microgels, poly[di(ethylene glycol) methyl ether methacrylate-co-2-methoxyethyl acrylate] poly(DEGMMA-co-MEA) microgels, were synthesized. The poly(DEGMMA-co-MEA) microgels were thermo-sensitive and exhibited a volume phase transitive temperature (VPTT) of 14-22 ℃. The incorporation of hydrophobic comonomer MEA shifted the VPTT of poly(DEGMMA-co-MEA) microgels to lower temperatures. The interfacial interaction of poly(DEGMMA-co-MEA) microgels and three model proteins, namely fibrinogen, bovine serum albumin and lysozyme, was investigated by quartz crystal microbalance (QCM). An injection sequence of microgel-after-protein was then established for the real-time study of the interaction of proteins and the microgels at their swollen and collapsed states by using QCM technique. The results indicated that the interfacial interaction of poly(DEGMMA-co-MEA) microgels and adsorbed protein layers was mainly determined by the electrostatic interaction. Because poly(DEGMMA-co-MEA) microgels were negatively charged in Tris-HCl buffer solution (pH = 7.4), the microgels did not adsorb on negatively charged fibrinogen and bovine serum albumin layers but strongly adsorbed on positively charged lysozyme layer. Stronger interaction between lysozyme and the microgels at collapsed state (i.e. at 37 ℃) was observed. Furthermore, the incorporation of MEA might weaken the interaction between poly(DEGMMA-co-MEA) microgels and proteins.
Electrosynthesis and Characterization of Aminomethyl Functionalized PEDOT with Electrochromic Property
Hui Sun , Bao-yang Lu , Du-fen Hu , Xue-min Duan , Jing-kun Xu , Shi-jie Zhen , Kai-xin Zhang , Xiao-fei Zhu , Li-qi Dong , Dai-ze Mo
2015, 33(11): 1527-1537  doi: 10.1007/s10118-015-1693-0
[Abstract](599) [FullText HTML] [PDF 0KB](0)
Abstract:
We herein report the electrosynthesis of an aminomethyl functionalized poly(3,4-ethylenedioxythiophene) (PEDOT) derivative, poly(2¢-aminomethyl-3,4-ethylenedioxythiophene) (PEDOT-MeNH2), in CH2Cl2-Bu4NPF6 (0.1 molL-1) system containing 2% boron trifluoride diethyl etherate (BFEE). The electrochemical behavior, structure characterization, thermal properties and surface morphology of this novel polymer were systematically investigated by cyclic voltammetry (CV), Fourier-transform infrared spectroscopy (FTIR), thermogravimetry (TG) and scanning electron microscopy (SEM), respectively. Electrochemistry results demonstrated that PEDOT-MeNH2 film displayed good redox properties and high electrochemical stability. Besides, PEDOT-MeNH2 films exhibited the electrochromic nature with obvious color changing from purple in the reduced form to blue upon oxidation. By further investigation, kinetic studies revealed that PEDOT-MeNH2 film had decent contrast ratio (41.8%), favorable coloration efficiency (152.1 cm2C-1), low switching voltages and moderate response time (2.4 s). Satisfactory results implied that the obtained PEDOT-MeNH2 film is a promising optoelectronic material and holds promise for electrochromic devices and display applications.
Shear-induced Crystallization in Phase-separated Blends of Isotactic Polypropylene with Ethylene-Propylene-Diene Terpolymer
Gui-qiu Ma , Da Li , Jing Sheng
2015, 33(11): 1538-1549  doi: 10.1007/s10118-015-1705-0
[Abstract](575) [FullText HTML] [PDF 0KB](0)
Abstract:
The compatibility between isotactic polypropylene (iPP) and ethylene-propylene-diene terpolymer (EPDM) in the blends was studied. SAXS analysis indicates that iPP and EPDM phases in the binary blend are incompatible. Isothermal crystallization behaviors of iPP in phase-separated iPP/EPDM were studied by in situ POM equipped with a Linkam shear hot stage. It was found that typical spherulites of iPP were formed both in neat iPP and in iPP/EPDM blends. The radial growth rate (dR/dt) of spherulites of iPP in the blend was not influenced by EPDM phases. Further investigations on isothermal crystallization of iPP in iPP/EPDM after shear with a fixed shear time showed that the crystallization rate of iPP in the blends increased with increasing shear rates, whereas, the crystallization rate was much lower than that of neat iPP. WAXD results showed that -crystal iPP was formed in neat iPP as well as in iPP/EPDM blends after shearing and the percentage of -crystal bore a relationship to the applied shear rate. The presence of EPDM resulted in lower percentage of -crystal in the blends than that in neat iPP under the same constant shear conditions. SAXS experiments revealed that shear flow could induce formation of oriented lamellae in iPP and iPP in the blends, and the presence of EPDM led to a reduced fraction of oriented lamellae.
The Effect of Particle Shape on the Structure and Rheological Properties of Carbon-based Particle Suspensions
Ran Niu , Jiang Gong , Dong-hua Xu , Tao Tang , Zhao-yan Sun
2015, 33(11): 1550-1561  doi: 10.1007/s10118-015-1704-1
[Abstract](586) [FullText HTML] [PDF 0KB](0)
Abstract:
The structure and rheological properties of carbon-based particle suspensions, i.e., carbon black (CB), multi-wall carbon nanotube (MWNT), graphene and hollow carbon sphere (HCS) suspended in polydimethylsiloxane (PDMS), are investigated. In order to study the effect of particle shape on the structure and rheological properties of suspensions, the content of surface oxygen-containing functional groups of carbon-based particles is controlled to be similar. Original spherical-like CB (fractal filler), rod-like MWNT and sheet-like graphene form large agglomerates in PDMS, while spherical HCS particles disperse relatively well in PDMS. The dispersion state of carbon-based particles affects the critical concentration of forming a rheological percolation network. Under weak shear, negative normal stress differences (N) are observed in CB, MWNT and graphene suspensions, while N is nearly zero for HCS suspensions. It is concluded that the vorticity alignment of CB, MWNT and graphene agglomerates under shear results in the negative N. However, no obvious structural change is observed in HCS suspension under weak shear, and accordingly, the N is almost zero.
Three-dimensional Numerical Simulation of Viscoelastic Phase Separation under Shear: the Roles of Bulk and Shear Relaxation Moduli
Jing-yi Chen , Zhong Jin , Ke-da Yang
2015, 33(11): 1562-1573  doi: 10.1007/s10118-015-1711-2
[Abstract](650) [FullText HTML] [PDF 0KB](0)
Abstract:
The morphological, dynamic and rheological characteristics in the viscoelastic phase separation (VPS) of sheared polymer solutions are investigated by three-dimensional (3D) numerical simulations of viscoelastic model. The simulations are accelerated by graphic process unit (GPU) to break through the limitation of computation power. Firstly, the morphological and dynamic characteristics of VPS under shear are presented by comparing with those in classic phase separation (CPS). The results show that the phase inversion and phase shrink take place in VPS under shear. Then, the roles of bulk and shear relaxation moduli in VPS are investigated in details. The bulk relaxation modulus slows down the phase separation process under shear, but not affects the dynamic path of VPS. The dynamic path can be divided into three stages: freezing stage, growth stage and stable stage. The second overshoot phenomenon in the shear stress is observed, and explained by the breakdown and reform of string structures. The shear modulus affects morphology evolution in the late stage of VPS under shear.
Rheological Behaviors of a Series of Hyperbranched Polyethers
Xue-pei Miao , Yan-shuang Guo , Li-fan He , Yan Meng , Xiao-yu Li
2015, 33(11): 1574-1585  doi: 10.1007/s10118-015-1707-y
[Abstract](577) [FullText HTML] [PDF 0KB](0)
Abstract:
Hyperbranched polyethers with different structures and molecular weights (MW) were synthesized using the A2+B3 approach by varying monomer ratio, A2 structure, and reaction time. Effects of backbone structure and MW on melt rheological behaviors were investigated by both small amplitude oscillatory shear and steady shear measurements. Master curves were constructed using the time-temperature superposition principle and compared. In the reduced frequency range covered, lgG~lg(aT) always show a slope of 1.0, suggesting a terminal zone behavior; in contrast, unexpected step changes or plateaus are observed on lgG' master curves. Effects of backbone structure and MW on master curves were discussed. The Cox-Merz rule was tested at different temperatures and was found to be applicable when flow instability was absent.
Comparison of Chain Structures between High-speed Extrusion Coating Polyethylene Resins by Preparative Temperature Rising Elution Fractionation and Cross-fractionation
Yan-hu Xue , Shu-qin Bo , Xiang-ling Ji
2015, 33(11): 1586-1597  doi: 10.1007/s10118-015-1709-9
[Abstract](574) [FullText HTML] [PDF 0KB](0)
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Two polyethylene (PE) resins (samples A and B) are synthesized as high-speed extrusion coatings with similar minimum coating thickness and neck-in performance but different maximum coating speeds. Both samples are separated into seven fractions using preparative temperature rising elution fractionation. The microstructures of the original samples and their fractions are studied by high-temperature gel permeation chromatography, Fourier transform infrared spectroscopy, 13C nuclear magnetic resonance spectroscopy, differential scanning calorimetry, and successive self-nucleation/annealing thermal fractionation. Compared with sample B, sample A has a broader MWD, more LCB contents, and less SCB contents. Moreover, sample A contains slightly more 30 ℃ and 50 ℃ fractions with lower molecular weights, and more fractions at 75 ℃ and 85 ℃ with higher molecular weight. The chain structure and its distribution in the two PE resins are studied in detail, and the relationship between the chain structure and resin properties is also discussed.
Biodegradable Microspheres with Poly(N-isopropylacrylamide) Enriched Surface: Thermo-responsibility, Biodegradation and Drug Release
Yin Yuan , Pei-jian Sun , Xu-dong Shi , Zhi-hua Gan , Fo-song Wang
2015, 33(11): 1598-1605  doi: 10.1007/s10118-015-1702-3
[Abstract](625) [FullText HTML] [PDF 0KB](0)
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Microspheres with thermo-responsible surface were fabricated by PCL-b-PEO-b-PNIPAM triblock copolymers. Thermo-responsible morphological changes of PCL-b-PEO-b-PNIPAM microspheres immersed in aqueous solution at temperatures above the LCST (e.g. 37 ℃) were observed from porous surface structure to compact surface layer. Enzymatic degradation and in vitro drug release results showed that the thermo-responsible surface layer greatly influenced the degradation of microspheres as well as the drug release behavior from microspheres. With the copolymerization of PNIPAM block into PCL-b-PEO copolymers, the drug release could be well regulated by changing temperatures and microspheres composition, which revealed the great potentials of microspheres with thermo-responsible surface for controlled drug release.
Synthesis and Characterization of Carborane Bisphenol Resol Phenolic Resins with Ultrahigh Char Yield
Shi-cheng Qi , Guo Han , Hong-rui Wang , Ning Li , Xiao-a Zhang , Sheng-ling Jiang , Ya-fei Lu
2015, 33(11): 1606-1617  doi: 10.1007/s10118-015-1712-1
[Abstract](571) [FullText HTML] [PDF 0KB](0)
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Two carborane-containing resol phenolic resins (P1 and P2) with high boron content were synthesized via the reaction of carborane bisphenols (1 and 2) with formaldehyde in the presence of alkaline. HRMS results indicate that P1 is mainly composed of hydroxymethylated o-carborane bisphenols, the Mw of which was restrained around 500 due to the strong steric hindrance of o-carborane bisphenol. In contrast, the molecular weight of P2 was well regulated under various reaction conditions. The obtained resins were characterized with spectroscopic techniques including FTIR, 1H-NMR, 13C-NMR, and 11B-NMR, which gave satisfactory results. TGA studies show that P2 shows char yield of 88.9% and 92.9% at 900 ℃ under nitrogen and air respectively. The imported carborane cage endows phenolic resin with ultrahigh char yield. Particularly, the char yield of the obtained carborane-containing phenolic resin under air is higher than that under nitrogen. FTIR and XRD confirm that the carborane cage could react with oxygen to form B2O3 at elevated temperatures, which postpones the thermal decomposition of phenolic resin and accounts for the high char yield.
Asymmetric Polymerization of N-Vinylcarbazole with Optically Active Anionic Initiators
Wei Hu , Jing Cao , Yi-ling Huang , Sai Liang
2015, 33(11): 1618-1624  doi: 10.1007/s10118-015-1689-9
[Abstract](582) [FullText HTML] [PDF 0KB](0)
Abstract:
The anionic polymerization of N-vinylcarbazole (NVC) by using optically active anionic initiators such as the lithium salts of (S)-1-(9H-fluoren-2-yl)-4-isopropyl-4,5-dihydrooxazole ((S)-1-FIDH) and (S)-2-(9H-fluoren-2-yl)-4-isopropyl-4,5-dihydrooxazole ((S)-2-FIDH) and complexes of (-)-Sparteine with n-butylithium (n-BuLi-(-)-Sp) or fluorenyl lithium (FILi-(-)-Sp) was achieved. The yield and specific rotation of poly(N-vinylcarbazole)s (poly(NVC)s) were considerably affected by the molar ratio of (S)-FIDH to NVC. The highest yield and specific rotation were obtained with Li-(S)-1-FIDH as an initiator, with a molar ratio of monomer and initiator [M]/[I] = 10/1. The effects of the chiral initiators, type of solvent and the polymerization temperature were investigated. The obtained optical activity of polymers was attributed to asymmetric induction of the chiral initiators.
The Banded Spherulites of iPP Induced by Pressure Vibration Injection Molding
Ren-xi La , Qi-xiong Zhou , Chao Xia , Da-shan Mi , Jie Zhang
2015, 33(11): 1625-1632  doi: 10.1007/s10118-015-1708-x
[Abstract](576) [FullText HTML] [PDF 0KB](0)
Abstract:
Isotactic polypropylene (iPP) samples obtained by pressure vibration injection molding (PVIM) and conventional injection molding (CIM) were studied by polarized-light microscopy (PLM), respectively. It was found that the alternating bright and dark banded spherulites were generated in the transitional region of PVIM parts. It is the first time that the banded spherulites of isotactic polypropylene were observed in polymer processing. What's more, the banded spherulites were proved to be constituted of a-form crystal by hot stage polarized-light microscopy (HT-PLM) and wide angle X-ray diffraction (WAXD). Morphology of the banded spherulites was also studied by scaning electronical microscopy (SEM).
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