The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
A series of heterografted PVSt-g-(PS/PE) based on polystyrene (PS) backbone with mixed PS and polyethylene (PE) side chains was obtained, in which the branching density of PVSt-g-(PS/PE) was above 72%. Because of the extremely short backbone, long side chains and high branching density in these comb-like copolymers, the topological structure of PVSt-g-(PS/PE) was similar to asymmetrical star copolymers...
The influence of oleic acid modified Fe3O4 (OA-Fe3O4) nanoparticles on the morphology and foaming behavior of cocontinuous linear low density polyethylene/polystyrene (LLDPE/PS) immiscible blends (60/40 by weight) was studied. The morphology observation showed that the addition of nanofillers resulted in the increased dispersion degree of both LLDPE and PS components and even the transformation of...
Comb-like block copolymers PVSt-g-(PS-b-PE) (PVSt: poly(4-(vinylpheneyl)-1-butene)) with high grafting density were successfully synthesized based on “Graft onto” strategy. The grafting density of PVSt-g-(PS-b-PE) was 35–39% (branch chain number per 100 repeating units of the backbone). By introducing PS block in the side chains, the total PS volume fraction in the copolymers could be adjusted to...
A new method to in situ synthesize polyethylene/polystyrene-g-polyethylene (PE/PS-g-PE) alloy based on hydrozirconation reaction with Cp2ZrHCl and coordination polymerization was reported. Hydrozirconation of vinyl-containing polystyrene (copolymer of styrene and 4-(vinylphenyl)-1-butene (PSVS)) was found to be an efficient way for immobilization of zirconocene pre-initiator onto polymer backbone...
A series of model comb-like polymers (PSVS-g-PS) with high branching degree were synthesized by nucleophilic substitution reaction between iodinated copolymer of styrene (St) with 4-(vinylphenyl)-1-butene (VSt) (PSVSI, backbone) and living polystyrene lithium (PSLi, side chain). This method is a facile way for modular synthesis of graft copolymers based on living anionic polymerization and hydrozirconation...
The structure and rheological properties of graphene oxide (GO)/polydimethylsiloxane (PDMS) composites are examined as the molecular weight of PDMS and concentration of GO are varied. Clusters formed by GO sheets get smaller and disperse better with increasing molecular weight of PDMS, which results in the higher critical concentration to form network (Ccr). Moreover, at GO concentration just above...
Four dithiocarbamates with different chemical structures (S-Propyl N,N-dipropyldithiocarbamate, S-allyl N,N-dipropyldithiocarbamate, S-Propyl N-pyrrolocarbodithioate and S-allyl N-pyrrolocarbodithioate) were used to adjust the melt radical reaction of polypropylene (PP). The combined effects between activating group Z (N,N-dipropyl and N-pyrrolo) and leaving group R(allyl and propyl) in the dithiocarbamates...
The combination of fumed silica (SiO2) with carbon black (CB) for improving thermal stability, flame retardancy and mechanical properties of linear low density polyethylene (LLDPE) was investigated. The temperature at the maximum weight loss rate of LLDPE was dramatically increased by 92 °C, and the peak value of heat release rate measured by cone calorimeter was significantly reduced by 80.7%. The...
Several polypropylene-g-polystyrene (PP-g-PS) and polypropylene-g-poly(n-butyl acrylate) (PP-g-PnBA) graft copolymers with well-defined molecular structures, basing on the same PP-Br precursor, were synthesized via a combination of metallocene-catalyzed polymerization and ATRP. The structure–property relationships of the resultant graft copolymers were systematically investigated. The crystallization...
Three different heteroaromatic ring derivatives (coagents) were used to adjust the melt radical reaction of polypropylene (PP). From the results of high temperature 1 H NMR and high-temperature size-exclusion chromatography (HT-SEC), all the coagents could quickly convert the tertiary PP macroradicals into resonance stabilized macroradicals and effectively restrain the β-scission of PP macroradicals...
A series of polypropylene-g-poly(ethylene-co-1-butene) graft copolymers (PP-g-EBR) with well-defined long chain branched (LCB) molecular structures, basing on the same PP–BT precursor (PP–BT2), were used to study effects of EBR LCBs on the crystallization and foaming behaviors of PP-g-EBRs. The kinetics results of isothermal and nonisothermal crystallization verify the opposite effects of LCB structure...
The effectiveness of dithiocarbamates in mediating melt radical reaction during preparing long chain branched polypropylene (LCB-PP) was studied. 1 H NMR, FTIR, GPC-TALLS and rheological measurements were used to characterize the structure of the resultant LCB-PP. The results showed that adding dithiocarbamates could help forming more long chain branches on PP, and furthermore the chemical...
A grafting monomer (p-(3-butenyl)styrene, BS)) containing two carbon–carbon double-bonds with different reactivity was used in melt radical reaction to prepare long chain branched polypropylene (LCB-PP). High-temperature size-exclusion (HT-SEC) coupled with triple detectors, rheometer and NMR were used to characterize the microstructure of the resultant LCB-PP. BS showed double functions in mediating...
Molybdenum-phenolic resin (Mo-PR) was grafted onto the surface of multi-walled carbon nanotubes (MWCNTs) to obtain modified MWCNTs (CNT-PR). Compared to epoxy resin, epoxy resin/CNT-PR nanocomposites showed the improvements in flame retardancy and mechanical properties. Structural characterization showed that the grafted Mo-PR improved the dispersion of MWCNTs in epoxy resin and enhanced the interfacial...
A new type of multifunctional ammonium modifier with carbonyl group and vinyl group was synthesized to prepare multifunctional montmorillonites (F-MMTs), which were used as multifunctional catalyst supports for in situ ethylene polymerization. High loading of metallocene catalyst in the galleries of F-MMT had been achieved due to the presence of carbonyl group in the multifunctional modifier. XRD...
Effect of copper N,N-dimethyldithiocarbamate (CDD) on melt reactions during preparing long chain branched polypropylenes (LCB-PP) via free radical grafting was studied. The structure and rheological properties of the modified PPs were characterized. The results showed that CDD could efficiently control two side reactions, i.e. degradation of PP backbone and homopolymerization of multifunctional monomer...
The effect of combination between a trace of halogenated compounds (such as ferric chloride and ammonium bromide) and Ni 2 O 3 particles on the carbonization of polypropylene (PP) was investigated during combustion. The results showed a synergistic catalysis of combined halogenated compounds with Ni 2 O 3 in promoting the formation of the residual char during combustion...
Effects of organically modified montmorillonites (OMMTs) with different type and amount of modifiers on flame retardancy of polystyrene (PS) have been studied. The results from morphology analysis, gas chromatography–mass spectrometry and cone calorimeter have showed different mechanisms for the flame retardancy of PS/OMMTs composites, depending on surface property of OMMTs. One is the catalysis of...
By reducing the attraction between the platelets of octadecylammonium chloride modified montmorillonite (OMMT-C18) via pre-intercalation of maleated polypropylene (MAPP), OMMT-C18 was exfoliated in thermoplastic polyurethane (TPU) matrix during melt-mixing. Wide angle X-ray diffraction, transmission electron microscopy and thermogravimetric analysis were used to investigate the microstructure of TPU...
Three kinds of organically modified Na + -montmorillonites (OMMTs), including two kinds of octadecylammonium modified montmorillonite with different contents of octadecylammonium and a kind of sodium dodecylsulfonate (SDSo) modified montmorillonite, were used to prepare polyamide 12 (PA12)/OMMT nanocomposites. Effects of the modifiers on degradation and fire retardancy of PA12/OMMT nanocomposites...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.