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.
The work aims to interpret the phase behavior of multi-polymers in super critical CO2 via a spatially dependent structural parameter, the monomer sequence distribution, rather than traditional statistical factors. Well-defined statistical copolymers based on three CO2-philic monomers, vinyl acetate, vinyl butyrate and vinyl butyl ether, were synthesized with reversible addition-fragmentation chain...
The synthesis of biodegradable hydrogels with both good mechanical properties and high water content is still a great challenge. In this study, a simple and scalable strategy for the preparation of a biodegradable polyurethane prepolymer composed of isocyanate terminated linear polyethylene glycol (L-PEG) and isocyanate terminated three-armed poly(l-lactic acid) (T-PLLA) is described. When mixed with...
Reversible transition of self-assembly and disassembly for PS720-P2VP200-PEO375 multicompartment micelles in aqueous solution induced solely by changing temperature has been investigated. The shuttle-like micelles, formed from a second self-assembly of nano-sized spheres at 20 °C, will disassemble to small spherical micelles as the temperature increases to 40 °C. Cooling the system back to 20 °C regenerates...
Surface-initiated ring-opening metathesis polymerization (SI-ROMP) was employed to prepare polymer-grafted graphene oxide (GO). Grubbs catalysts were immobilized onto GO surfaces followed by ROMP of norbornene from these active catalyst sites to result in polynorbornene (PNb)-functionalized GO (GO-PNb), whose structure and morphology were fully characterized by FTIR, Raman, NMR, XRD, TGA and SEM....
Stereoregular high polymers of poly(l-lactic acid) (PLLA) (M w 1.2 × 10 5 , isotacticity 96.0%) and poly(d-lactic acid) (PDLA) (M w 1.0 × 10 5 , isotacticity 98.6%) were successfully synthesized via melt/solid polycondensation (MP/SSP) using a biogenic catalyst creatinine (CR). The follow-up monitor of the polycondensation products with 13 C NMR technique revealed...
Mussel-inspired catechol-containing polymers have drawn great attention due to their outstanding adhesive properties. Catechol-containing polyethylene glycol (cPEG) is a well-studied catechol-containing polymer used for tissue repair. Nevertheless, catechols can only be attached to the chain ends of polyethylene glycols thus the bonding strength of the resulting polymers is limited. Aiming at solving...
Isotactic polycondensation of l-lactic acid (LLA) catalyzed by biogenic creatinine was carried out at 140–175 °C under sequentially reduced pressure (30–10 torr). The product poly-LLA (PLLA) possesses high optical purity (e.e. 96.1–98.7%) as well as narrow molecular weight distribution (PDI 1.74–1.85). 13 C NMR follow-up monitor of the polymerization demonstrated that the isotacticity of PLLA...
A convenient method of tuning aggregate morphologies from amphiphilic block copolymer by adding second selective solvent is introduced in this paper. Some novel aggregate morphologies, i.e. hierarchical vesicles (and compound spherical micelles) with one or more tails, were formed by introducing a second selective solvent for core-forming blocks into the poly(4-vinyl pyridine)-b-polystyrene-b-poly(4-vinyl...
It was theoretically pointed out that the product of the yield stress and yield strain of matrix polymer that determined the brittle-ductile transition (BDT) of particle toughened polymers. For given particle and test condition, the higher the product of the yield stress and the yield strain of the matrix polymer, the smaller the critical interparticle distance (ID c ) of the blends was. This...
The toughness of polypropylene (PP)/ethylene–propylene–diene monomer (EPDM) blends was studied over wide ranges of EPDM content and temperature. In order to study the effect of notch radius (R), the toughness of the samples with different notch radii was determined from Izod impact test. The results showed that both toughness and brittle–ductile transition (BDT) of the blends were a function of R,...
In the framework of lattice fluid model, the Gibbs energy and equation of state are derived by introducing the energy (E s ) stored during flow for polymer blends under shear. From the calculation of the spinodal of poly(vinyl methyl ether) (PVME) and polystyrene (PS) mixtures, we have found the influence of E s on equation of state in pure component is inappreciable, but it is appreciable...
In this study, we established a correlation between cavitations volume and the brittle–ductile transition (BDT) for particle toughened thermoplastics. The brittle–ductile transition temperature (TBD) was calculated as a function of T∗ and interparticle distance (ID), respectively, where T∗ was a parameter related to the volume of cavitations. The results showed that the smaller the cavitations volume,...
The effect of the elastomer stiffness on brittle-tough transition in elastomer toughening thermoplastics was quantitatively studied. A correlation between brittle-tough transition temperature and the elastomer stiffness was obtained. The calculation from this correlation showed that the brittle-tough transition temperature (T bt ) of elastomer toughening thermoplastics slowly increased...
Blends of nylon-6 and epoxidised ethylene propylene diene (eEPDM) rubber were prepared through reactive mixing. It is found that the toughness of nylon-6 can be much improved by this method, and that the particle size of eEPDM is much smaller than that of unexpoxidised EPDM (uEPDM) rubber in a nylon-6 matrix. This indicates that the epoxy group in eEPDM could react with a nylon-6 end group to form...
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.