Three Kinds of Films Obtained from Plasma Poly-merization of Octamethylcyclotetrasioxane

Three kinds of 'films' i.e. cross-linked film, grainy film and transparent film, wereobtained in the process of plasma polymerization of Octamethylcyclotetrasioxane(D4) under dif-ferent conditions. From SEM photos, we can see that the cross-linked film has a network form.From XPS spectra, we can see that the content of Si-C bond of the cross-linked film is lower thanthat of the transparent film, and this result agrees well with the test results of FTIR spectra. Thisproves that the c1eavage of the Si-C bond and C-H bond are the main cleavage in the formationof cross-linked film, whereas the cleavage of the Si-O is the main cleavage in the formation oftransparent film. In order to enhance the collision of the reactive particles and investigate theinfluence of magnetic field on the plasma polymerization, we introduced the magnetic field, as aresult, we got the grainy film.

Highly Active New α-Diimine Nickel Catalyst for Polymerization of Ethylene

A new α-diimine ligand 1a, bis[N,N′-（4-tert-butyl-2,6-dimethylphenyl）imino]-2,3-butanediylidene and its corresponding Ni（II） complex 2a, {bis[N,N′-（4-tert-butyl-2,6-dimethylphenyl）imino]-2,3-butanediylidene}dibromo- nickel were successfully synthesized, and characterized by 1H NMR, 13C NMR, Fourier transform infrared spectroscope（FTIR）, elemental analysis and X-ray photoelectron spectroscopy（XPS）. α-Diimine ligand 1b, bis[N,N′-（2,6- dimethylphenyl）imino]-2,3-butanediylidene and its corresponding Ni（II） complex 2b, {bis[N,N′-（2,6-dimethyl- phenyl）imino]-2,3-butanediylidene}dibromonickel were also synthesized and characterized for comparison. The pre-catalyst 2a with sterically bulky, electron-donating group tert-butyl, activated by diethylaluminum chloride （DEAC） and tested in the polymerization of ethylene, was very highly active[2.01×107 g PE/（mol Ni？h？0.1 MPa）] and led to a very highly branched polyethylene（ca. 35―103 branches/1000 C）. The state of the polyethylene obtained varied from plastic, elastomer polymers to the oil-like hyperbranched polymers.

Time-dependent Diffusion Coefficient and Conventional Diffusion Constant of Nanoparticles in Polymer Melts by Mode-coupling Theory

Time-dependent diffusion coefficient and conventional diffusion constant are calculated and analyzed to study diffusion of nanoparticles in polymer melts. A generalized Langevin equa- tion is adopted to describe the diffusion dynamics. Mode-coupling theory is employed to calculate the memory kernel of friction. For simplicity, only microscopic terms arising from binary collision and coupling to the solvent density fluctuation are included in the formalism. The equilibrium structural information functions of the polymer nanocomposites required by mode-coupling theory are calculated on the basis of polymer reference interaction site model with Percus-Yevick closure. The effect of nanoparticle size and that of the polymer size are clarified explicitly. The structural functions, the friction kernel, as well as the diffusion coefficient show a rich variety with varying nanoparticle radius and polymer chain length. We find that for small nanoparticles or short chain polymers, the characteristic short time non-Markov diffusion dynamics becomes more prominent, and the diffusion coefficient takes longer time to approach asymptotically the conventional diffusion constant. This constant due to the microscopic contributions will decrease with the increase of nanoparticle size, while increase with polymer size. Furthermore, our result of diffusion constant from mode- coupling theory is compared with the value predicted from the Stokes-Einstein relation. It shows that the microscopic contributions to the diffusion constant are dominant for small nanoparticles or long chain polymers. Inversely, when nanonparticle is big, or polymer chain is short, the hydrodynamic contribution might play a significant role.

Preparation and performance of novel thermal stable composite nanofiltration membrane

The novel thermal stable composite nanofiltra-tion membranes were prepared through the interfacial polymerization of piperazine and trimesoyl chloride on the poly(phthalazinone ether)ultrafiltration substrate.The effects of polymerization and testing conditions on membrane performance were studied.The surface morphologies of the substrate and the composite mem-branes were observed by means of scanning electron microscopy(SEM)and atomic force microscopy(AFM).The separation properties of membranes for dyes and salts were tested.The composite membranes show good ther-mal stability.The rejection for Na2SO_(4) was kept over 96%,1.0 MPa and 80℃.When tested at 1.0 MPa and 60℃,the rejection of the composite membrane for dyes was kept at the rejection for NaCl was lower than 20%.

Adsorption of 1,3-propanediol from synthetic mixture using polymeric resin as adsorbents

The aim of this work was to separate 1,3-PDO from a synthetic mixture using polymeric resins,Amberlite XAD-7 and XAD-16 resins.The equilibrium adsorption of 1,3-PDO onto two polymeric resins were investigated in binary and tertiary systems.Experimental results of binary component adsorption equilibrium indicated that the adsorption capacity(q)of 1,3-PDO at 160 g/L onto XAD-7 and XAD-16 was 835.96 and 584.61 mg 1,3-PDO/g dry resin,respectively.The adsorption isotherms were closely predicted by the Langmuir-Freundlich model among the two isotherm model tested.The value of n of 1,3-PDO adsorbed on XAD-7 are much higher than those on XAD-16.This result suggested that XAD-7 resin has a higher affinity for the 1,3-PDO adsorption than XAD-16 resin.Moreover,the value of adsorption capacity of 1,3-PDO in the binary and tertiary component were compared at the same conditions.In the tertiary system,although the selectivity of 1,3-PDO from XAD-7 was approximately six times higher than XAD-16,the adsorption capacity of 1,3-PDO at 160 g/L onto XAD-16 was higher than XAD-7.Interestingly,the reusability of XAD-7 and XAD-16 resins in the three cycle times shows a slight loss of adsorption capacity.Furthermore,the investigation about desorption by an ethanol/water mixture at 50%(V/V)indicated that the desorption yield of 1,3-PDO from XAD-7 was lower than XAD-16 resin for both the binary and tertiary component.This was due to the more favorable adsorption characteristics of XAD-7 resin than XAD-16 resin.

TM-pass polarizer based on multilayer graphene polymer waveguide

A TM-pass polarizer based on multilayer graphene polymer waveguide is proposed and theoretically analyzed.The mode properties,the extinction ratio,the insertion loss and the bandwidth are also discussed.The results show that a TM-pass polarizer,which only guides the TM mode,can be achieved by multilayer graphene polymer waveguide.With length of 150μm,the proposed polarizer can achieve extinction ratio of 33 dB and insertion loss of 0.5 d B at optical wavelength of 1.55μm.This device has an excellent performance,including large extinction ratio and low insertion loss within the spectral range from 1.45μm to 1.6μm.