DESIGN AND SYNTHESIS OF NOVEL CHIRAL IONIC LIQUIDS AND THEIR APPLICATION IN FREE RADICAL POLYMERIZATION OF METHYL METHACRYLATE

Two new chiral ionic liquids, 1-((-)-menthoxycarbonylmethylene)-3-methylimidazolium hexafluorophosphate and l-((-)-menthoxycarbonylmethylene)-3-hexadecylimidazolium hexafluorophosphate, were designed and prepared. Their chemical structures were characterized by 1H-NMR. Reverse atom transfer radical polymerization of methyl methacrylate(MMA) in these two ionic liquids was carried out using AIBN/CuC12/bipy as the initiating system. The resultant well-defined polymethyl methacrylate (PMMA) was employed as a macroinitiator to induce the atom transfer radical polymerization of menthyl methacrylate (MnMA) in chlorobenzene, which yielded a PMMA-b-PMnMA diblock copolymer with narrow polydispersity.

"LIVING" FREE RADICAL SYNTHESIS OF NOVEL RODCOIL DIBLOCK COPOLYMERS WITH POLYSTYRENE AND MESOGEN-JACKETED LIQUID CRYSTAL POLYMER SEGMENTS

The synthesis of rod-coil diblock copolymers was achieved for the firsttime by TEMPO-mediated 'living' free radical polymerization of styrene and 2,5-bis[(4-methoxyphenyl)oxycarbonyl]styrene(MPCS). The block architecture of the two diblockcopolymers thus prepared, MPCS-b-St(5400/2400) and MPCS-b-St(10800/8700), was con-firmed by GPC, DSC studies and the formation of multimolecular micelles.

PHOTOPOLYMERIZATION OF PROPARGYL ACETATE WITH MICHLER’S KETONE AS PHOTOINITIATOR

Photopolymerization of propargyl acetate (PAT) with Michler’s ketone (MK) asphotoinitiator in benzene has been investigated for the first time. Some features of the PATphotopolymerization with MK as photoinitiator is described.

SIMULTANEOUS SAXS/WAXS/DSC STUDIES ON MICROSTRUCTURE OF CONVENTIONAL AND METALLOCENE-BASED ETHYLENE-BUTENE COPOLYMERS

The fractions of one metallocene-based (mPE) and one conventional (znPE) ethylene-butene copolymer eluted at from temperature rising elution fractionation were selected for DSC and time-resolved small angle X-ray scattering (SAXS) and wide angle X-ray scattering (WAXS) characterization. The DSC and WAXS results show that two crystal structures exist in both mPE and znPE: structure A with higher melting temperature and structure B with lower melting temperature. It was found that original znPE (s-znPE) contains more highly ordered structure A than original mPE (s-mPE) in spite of the higher comonomer content of znPE. Another structure C is also identified because of higher crystallinity measured by WAXS than by DSC and is attributed to the interfacial region. The SAXS data were analyzed with correlation function and two maxima were observed in s-mPE and s-znPE, in agreement with the conclusion of two crystal populations drawn from DSC and WAXS results. These two crystal populations have close long periods in s-mPE, but very different long periods in s-znPE. In contrast, freshly crystallized mPE and znPE (f-mPE and f-znPE) contain only a single crystal population with a broader distribution of long

Photocuring Behaviors of UV-Curable Perfluoropolyether-Based Fluoropolymers with and without Tertiary Amine

UV-curable perfluoropolyether (PFPE)-based fluoropolymer (PFPE-DMA) was synthesized and the photocuring behaviors of PFPE-DMA/HDDA systems with and without tertiary triethyl amine (TEA) were investigated using photo-DSC under air and nitrogen atmospheres. Photo-DSC analysis revealed that N2 purging and the presence of TEA mitigated oxygen inhibition in the photopolymerization of the UV-curable free-radical PFPE-DMA/ HDDA system. In addition, TEA synergistically acted as a coinitiator or photosynergist under nitrogen atmosphere, which increased the cure rate and percentage conversion for the photopolymerization of PFPE-DMA/ HDDA. TEA acted as both oxygen scavenger and photosynergist. The results presented here demonstrate that investigating the photocuring behaviors of PFPE-DMA/HDDA systems is very helpful to determine the optimal curing conditions for the PFPE-DMA fluoropolymer.

SYNTHESIS AND PROPERTIES OF NEW SIDE-CHAIN LIQUID CRYSTALLINE POLYMER WITH LATERALLY ATTACHED MESOGENS BY ESTER GROUP

New liquid crystalline monomer, 2,5-bis[(4’-methoxyphenoxy)carbonyl]phenyl acrylate wassuccessfully synthesized. Polyacrylate with laterally attached mesogens via ester linkage was also derived.This polymer forms an enantiotropic liquid crystal phase while its monomer exhibits a metastable nematicphase with respect to the crystalline state. However, its liquid crystallinity is very low as compared to that ofpoly{2,5-bis[(4’-methoxyphenoxy)carbonyl]-styrene}.

SUPPORTED CATALYST WITHOUT EXTERNAL ELECTRON DONOR FOR PROPYLENE POLYMERIZATION Ⅱ. TACTICITY DISTRIBUTION AND MICROSTRUCTURE OF POLYPROPYLENE

Propylene was polymerized with a novel supported Ziegler-Natta catalystcontaining 2,2-di-iso-butyl-1,3-dimethoxy-propane （DIBDMP） as internal donor and in theabsence of external donor. The tacticity distribution of polypropylene was obtained by usingtemperature rising elution fractionation （TREF） technique and microstructure of fractionswas studied with 13C-NMR. Compared with the catalyst without electron donor, this cat-alyst gives a considerably narrower tacticity distribution. Fractionation data demonstratethat DIBDMP shows better performance than aromatic diester DNBP （di-n-butyl phtha-late）. Chemically inverted propylene units and less stereoblockiness are found in the firstfraction. Possible reasons for these were presented.

STRUCTURE OF CRYSTALLINE DOMAINS IN SEMICRYSTALLINE BLOCK COPOLYMER THIN FILMS

Thin film morphology of a symmetric semicrystalline oxyethylene/oxybutylene diblock copolymer (E76B38) on silicon was investigated by tapping mode atomic force microscopy (AFM). It is found that the nascent thin film is composed of multiple polymer layers having mixed thicknesses of L≈L0 and L≈L0/2 (L0 is the long period of the block copolymer in bulk) besides the first layer near the substrate. This shows that the crystalline domain in the block copolymer consists of double poly(oxyethylene) layers. Annealing leads to disappearance of the polymer layers with thickness L≈L0/2, indicating that such polymer layers are metastable.

A NEW STRATEGY FOR THE DESIGN OF LIQUID CRYSTALLINE POLYMERS WITH FLEXIBLE AND APOLAR BUILDING BLOCKS

The synthesis and characterization of a new series of liquid crystalline polymers, poly(dicycloalkyl vinylterephthalate)s, are reported. The basic building blocks of these polymers are not mesogenic by themselves. However,very stable mesophases can be generated by self-assembly of the polymer molecules. This approach suggests a novel design strategy of liquid crystalline polymers with flexible and apolar building blocks.

NUCLEATION MECHANISM OF PEO BLOCK IN DOUBLE-CRYSTALLINE POLY(ETHYLENE-co-BUTENE)-b-POLY(ETHYLENE OXIDE) BLOCK COPOLYMERS

In this paper, we proposed a method to determine the nucleation effect of pre-existing crystals on crystallization of the second block in double crystalline block copolymers, which is usually covered by the suppression effect. The nucleation mechanism of poly(ethylene oxide) (PEO) block from the pre-crystallized polyethylene (PE) block in poly(ethylene-co butene)-b-poly(ethylene glycol) (EmEOn) diblock copolymers was investigated under variable crystallization environments. The crystallization environment for the PEO block was altered by cooling at different cooling rates or successive self-nucleation (SSN) to the PE block. It was found that the presence of nucleation effect is strongly dependent on composition of the block copolymers. The crystallization temperature (Tc) of PEO block in E174EO90 increases as cooling rate applied to the PE block decreases, indicating that PE block can nucleate the crystallization of PEO block and more perfect PE crystals have stronger nucleation effect. In E1822EO41 crystallization of the PEO block is confined, shown by the disappearance of self-nucleation domain, and the PE block has no nucleation effect on the crystallization of PEO block. Double crystallization peaks are observed for the PEO block in E182EO41 and the intensity of the crystallization peak at higher temperature increases as the PE crystals become more perfect. After exclusion of homogeneous nucleation mechanism, the higher temperature crystallization peak of the PEO block in E182EO41 is tentatively ascribed to surface nucleation.

EFFECT OF OVERLAP CONCENTRATION AND PERSISTENCE LENGTH ON DNA SEPARATION IN POLYMER SOLUTIONS BY ELECTROPHORESIS

The persistence length and the overlap concentration(c~*) of poly(ethylene oxide)(PEO) and hydroxyethylcellulose(HEC) with similar molecular weight in 1×TBE buffer were studied by laser light scattering and viscometry.Their effect on DNA separation was investigated by capillary electrophoresis.It was determined that the persistence length of HEC was at least 5 times higher than that of PEO.Therefore,the c~* of HEC was smaller than that of PEO by a factor of ca.2.5.It was also found that the c~* values de...

MEASUREMENTS OF CHAIN INTERPENETRATION OF POLYMER GLASSES

The concept of entanglement provides the basis of our current understanding of the flow behavior of polymer melts. Current techniques developed to investigate the degree of interpenetration of polymer chains only provide indirectly the information of the degree of entanglement in a relatively large scale (several to tens of nanometer). In this article, we report 1H-NMR spectroscopy with dipolar filters under fast magic angle spinning for probing chain interpenetration of polymer glasses at the molecular level.

CRYSTALLIZATION KINETICS OF ETHYLENE-PROPYLENE COPOLYMERS PREPARED BY LIVING COORDINATION POLYMERIZATION

In this paper,crystallization kinetics of a series of ethylene-propylene copolymers prepared by living polymerization coordination catalyzed by a fluorinated bis(phenoxyimine)Ti catalyst(FI-EP copolymers)was studied,and was compared with that of ethylene-propylene copolymers prepared by a conventional Ziegler-Natta catalyst(ZN-EP copolymers).It is found that,the Avrami exponent and the crystallization rate constant of the FI-EP and ZN-EP copolymer show similar dependence on crystallization temperature,bu...

Analysis of ATR-FTIR Absorption-Reflection Data from 13 Polymeric Fabric Materials Using Chemometrics

We used both correlation and covariance-principal component analysis (PCA) to classify the same absorption-reflectance data collected from 13 different polymeric fabric materials that was obtained using Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR). The application of the two techniques, though similar, yielded results that represent different chemical properties of the polymeric substances. On one hand, correlation-PCA enabled the classification of the fabric materials according to the organic functional groups of their repeating monomer units. On the other hand, covariance-PCA was used to classify the fabric materials primarily according to their origins;natural (animal or plant) or synthetic. Hence besides major chemical functional groups of the repeat units, it appears covariance-PCA is also sensitive to other characteristic chemical (inorganic and/or organic) or biochemical material inclusions that are found in different samples. We therefore recommend the application of both covariance-PCA and correlation-PCA on datasets, whenever applicable, to enable a broader classification of spectroscopic information through data mining and exploration.

Effects of Molar Ratios of Thiol-Ene Monomers on the Morphology and Electro-Optical Properties of Polymer Dispersed Liquid Crystal Films

We synthesized tetrafunctional allyl ether monomer (4-AE) and investigated the effects of the different molar ratios of trimethylolpropane tris-(3-mercaptopropionate) (3-SH) to 4-AE on the photopolymerization behavior, morphology, and electro-optical properties of thiol-ene-based PDLC films. Photo-DSC and DSC analyses revealed that the PDLC sample containing 45 wt% 3-SH and 45 wt% 4-AE gave the highest exotherm, the fastest photocure rate, and the highest Tg due to the matched stoichiometry. Morphological observations and electro-optical measurements showed that the PDLC sample with the matched molar ratio gave the smallest LC droplet size, the highest threshold, driving voltages, and lowest saturation transmittance because the orientation of LC molecules got difficulty in small droplets. The stoichiometric ratios of 3-SH to 4-AE played an important role in controlling the photocure rate, phase separation rate, microstructures of LC droplets, and electro-optical properties of thiol-ene-based PDLC systems.

SURFACE MODIFICATION OF POLYPROPYLENE MICROPOROUS MEMBRANE BY TETHERING POLYPEPTIDES

Two kinds of polypeptides were tethered onto the surface of polypropylene microporous membrane (PPMM) through a ring opening polymerization of L-glutamate N-carboxyanhydride initiated by amino groups which were introduced by ammonia plasma andγ-aminopropyl triethanoxysilane treatments. X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (FT-IR/ATR), scanning electron microscopy (SEM), together with water contact angle measurements were used to characterize the modified membranes. XPS analyses and FT-IR/ATR spectra demonstrated that polypeptides are actually grafted onto the membrane surface. The wettability of the membrane surface increases at first and then decreases with the increase in grafting degrees of polypeptide. Platelet adhesion and murine macrophage attachment experiments reveal an enhanced hemocompatibility for the polypeptide modified PPMMs. All these results give evidence that polypeptide grafting can simultaneously improve the hemocompatibility as well as reserve the hydrophobicity for the membrane, which will provide a potential approach to improve the performance of polypropylene hollow fiber microporous membrane used in artificial oxygenator.

GRAFTING OF PEROXIDE-INITIATED MALEIC ANHYDRIDE ON SPHERICAL PE/PPIN-REACTOR BLEND GRANULES

Spherical polyethylene/polypropylene (PE/PP) in-reactor blend granules with various ethylene/propylene molar ratios and high porosity were synthesized using a high yield TiCVMgCl2 supported catalyst. A solution of benzoyl peroxide (BPO)/maleic anhydride (MAH)/xylene (interfacial reagent) or BPO/MAH/St (comonomer) was absorbed onto the PE/PP in- reactor blend granules, and solid phase graft polymerization of MAH on PE/PP was conducted. The amount of grafted MAH on PE/PP was measured through chemical titration. The results showed that solid phase graft polymerization of MAH in PE/PP in-reactor blend granules produced graft copolymer with high amount of grafted MAH, and the amount of grafted MAH was raised slightly when St was introduced as comonomer. The graft in-reactor blend was fractionated into five fractions through temperature-gradient extraction fractionation (TGEF), and the fractions were analyzed by FTIR. The results revealed that MAH is mainly grafted on the PE segments, whereas MAH was predominantly grafted on the PP segments when St was present in the graft polymerization system. In addition, the final product is still in the form of regular spherical granules, which is beneficial for industrial processing.

FRACTIONATED CRYSTALLIZATION OF HDPE IN PS/POE/HDPE/SBS BLENDS

The fractionated crystallization behavior of the minor dispersed HDPE phase in PS/POE/HDPE/SBS quaternary blends was investigated by differential scanning calorimetry (DSC).Interestingly,we found that the fractionated crystallization behavior of HDPE was molecular weight dependent.At a fixed composition,HDPE with lower molecular weight showed more obvious fractionated crystallization behavior than HDPE with higher molecular weight.This was ascribed to a finer dispersion of HDPE with lower molecular weigh...

Effect of Silane Coupling Agent on the Flexural Property of Glass Fiber Reinforced Composite Film

Transparent glass fiber reinforced composites films ware fabricated by UV light induced chemical crosslinking of composite materials consisting of glass fiber and UV curable resin in film state. In order to apply film to flexible device, excellent flexural property is required, then the delamination should not occurred between glass fiber and UV curable resin when film is bent. To minimize delamination and improve the interfacial adhesion at interface between glass fiber and UV curable resin, the γ-aminopropyl triethoxy silane and γ-glycid oxypropyl trimethoxy silane were applied for the surface treatment of glass fibers. Silanization of glass fiber surface was checked by scanning electron microscopy and the degree of delamination of composite film was confirmed through the bending test, ASTEM290-96a, used by haze meter.

APPLICATION OF TIME-TEMPERATURE SUPERPOSITION PRINCIPLE TO EVALUATION OF SCATTERING INTENSITY EVOLUTION IN PHASE SEPARATION FOR PMMA/SAN BLENDS

Spinodal phase separation behavior of poly(methyl methacrylate)/poly(styrene-co-acrylonitrile)(PMMA/SAN)blends was investigated by the time-resolved small angle light scattering (SALS) technique. It was found that the influence oftemperature on the scattering intensity evolution followed the time-temperature superposition principle. The relationshipbetween temperature and the relaxation time of scattering intensity I(t) can be well described by the Williams-Landel-Ferry(WLF) function.