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Would the chain-scission mechanism of the polymer depolymerizations be changed by the non-thermal effects of microwave irradiation? and how are the chain-scission mechanism and its kinetic behaviors? In this paper, the kinetic processes and mechanisms of poly(ethylene terephthalate) (PET) hydrolytic depolymerization of microwave were investigated, and the chain-scission mechanism was further discussed to give effective support to the non-thermal effects of microwave irradiation for which chemical reactions of small molecules could not give effective evidences.
A novel fluorinated diamine monomer, 1,1′-thiobis-[(2-trifluoromethyl)4-aminophenoxy) naphthyl ether], was successfully synthesized in two steps route, including the Williamson etherification reaction, followed by catalytic reduction. A series of fluorine-containing poly(ether amide)s were synthesized from such diamine with various aromatic dicarboxylic diacids. These polymers were amorphous in nature, readily soluble in various organic solvents and exhibited high thermal stability and low refractive indexes.
A new kinetic model of styrene-free radical bulk polymerization was developed. Experimental data of styrene conversion dependence on reaction time were well described by estimated kinetic model. It was determined that the first-order reaction followed by autoacceleration of styrene-free radical bulk polymerization is taking place simultaneously between 41.7 and 110.5 °C.
The addition of methanol to dilute THF solutions of chiral-achiral random copolymers of fluorene derivatives and the chiral homopolymer showed thermo-reversible circular dichroism (CD) induction in the main-chain fluorene absorption region, demonstrating the uneven population of the right- and left-handed helical conformation in the polymer chains. From the sign of the induced CD, we found two helical screw-sense inversions by changing the chiral monomer content. The Ising model for chirally interacting chiral-achiral random copolymers can explain the double screw-sense inversions.
Functional non-woven fiber mats were prepared by combining the electrospinning method and surface-initiated atom transfer radical polymerization (ATRP). The surface-initiated ATRP of 3-(N-2-methacryloyloxyethyl-N,N-dimethyl) ammonatopropanesulfonate), 2-hydroxyethyl methacrylate and 2-(perfluorooctyl)ethyl acrylate proceeded successfully from the fiber surface of poly(methyl methacrylate)-co-poly(2-(2-bromoisobutyryloxy)ethyl methacrylate) without any structural changes. A grafted layer after the surface-initiated ATRP was observed by atomic force microscopy. Static contact angles against water were also evaluated to discuss the relationship between the roughness of the electrospun non-woven fiber mats and wettability.
The aligned nanofiber assemblies showed anisotropic wettability based on the high alignment degree of the nanofibers. The poly(3,4-ethylenedioxythiophene)/poly(4-styrene sulfonate) (PEDOT/PSS) composite film containing aligned nanofibers displayed an anisotropic actuation response when a voltage was applied in air. The orientation of the embedded nanofibers within the PEDOT/PSS matrix leads to the control of actuation direction because of the difference of anisotropic mechanical properties in the composite films.
We have synthesized novel Mussel-mimetic adhesive resin from biomass monomers. Because the adhesive resin contains catechol group at their chain ends, which is similar chemical structure of 3,4-dihydroxyphenyl-L-alanine (DOPA) produced by Mussel, it demonstrated strong adhesive characteristics onto organic and/or inorganic surfaces beyond the conventional instant superglue as shown in figures (X, conventional instant superglue; Y, poly(DHCA-co-4HCA) resin). The origin of this strong adhesive characteristic was discussed by strong type of hydrogen bond interaction between our new resins and oxidized and/or OH group on the substrates.
The three type water-soluble monocyclic aromatic (MA) polymers were synthesized; MA polymer has same molecular weight (MW), sulfonated phenol–formaldehyde (SPF) polymer with more –SO3 and less –OH functional groups, has high water-reduction percentage and high slump loss and poor workability preservation properties, the aminosulfonate–phenol–formaldehyde polymer (AS) and aminosulfonate–phenol–salicylic acid-formaldehyde (AH) polymer bonded –SO3 and –COOH as dispersion groups, −OH and –NH2 as fluidity preservation groups have better water-reducing capacity, workability preservation properties, setting time retardation of cement paste and higher compressive strengths of concrete.
