The Structure and Properties of Lysine Doped Polypeptide Modified Polypyrrole Nanoparticles

Lysine doped polypeptide modified particles were chemically synthesized in different weight ratios of polypeptide to Py feed. The microstructures of these PPys were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier Transform Infrared (FTIR). Semiconductor parameter analyzer, ubbelohde viscometer and rotation viscometer were used to characterize the electrical property, viscosity and solubility of these PPys. The results show that the polypeptide has the function as the template in the Py polymerization. The lysine doped PPys form many rings with diameters of about several micrometers, with the weight ratio increase, the ring structure become more obvious and the diameters of the rings decrease to about 200 nm. The conductivity of lysine doped polypeptide modified PPys synthesized with the weight ratio of 3:1 is about 1.73 × 10-3S/cm. It is mostly soluble in acetic acid, good soluble in the mixture of acetic acid and HFIP with a volume ratio of 2:1. Moreover, the solubility in the mixture of acetic acid and HFIP is little affected by weight ratio and maintain about 93.8%, indicating its good solubility in no toxicity solvent or very low toxicity solvent.

INFLUENCE OF CEMENT TYPE AND ADMIXTURES ON RHEOLOGICAL PROPERTIES OF CEMENT PASTE / CHEMINIŲ ĮMAIŠŲ POVEIKIS REOLOGINĖMS CEMENTO TEŠLOS SAVYBĖMS

The article aims to research the influence of the chemical admixtures on the rheological properties of Portland cement paste and determine their impact on the effectiveness of hydration induction period. Materials used in the study: Portland cement CEM I 42.5 (N and R early strength), limestone Portland cement CEM II/A-LL 42.5 N, plasticizer Centrament N3, the latest generation superplasticizer MC-PowerFlow 3140 and water. Investigations focused on effects of Plasticizer and superplasticizer on water and cement (W/C) ratio and Portland cement paste flow characteristics. Portland cement pastes with the same watercement ratio with and without chemical admixtures were tested. Investigations were carried out using a Suttard viscometer and rotation viscometer Rheotest NH 4.1 with coaxial cylinders. It was observed that viscosity of Portland cement paste can be controlled by chemical admixtures during the hydration induction period. Investigations of effectiveness of the chemical admixtures on the rheological properties of the Portland cement pastes, comparing it with a control composition of the Portland cement paste were provided in the article. Diagrams show changes of the viscosity of the Portland cement pastes depending on the type and amount of the used chemical admixtures. Obtained results were compared with the same consistence without admixtures. After making the regressive analysis of research results of Portland cement paste with and without chemical admixtures, empirical equations were produced. Santrauka Šio darbo tikslas – ištirti cheminių įmaišų poveikį reologinėms portlandcemenčio tešlų savybėms ir nustatyti jų poveikio veiksmingumą indukcinio hidratacijos periodo metu. Tyrimams naudotos šios medžiagos: AB „Akmenės cementas“ gamyklos portlandcementis CEM I 42,5 (N ir R ankstyvojo stiprumo), klinties portlandcementis CEM II/A-LL 42,5 N, plastiklis Centrament N3, naujausios kartos superplastiklis MC-PowerFlow 3140 ir vanduo. Ištirtas plastiklio ir superplastiklio poveikis vandens ir cemento (V/C) santykio pokyčiams ir portlandcemenčio tešlų sklidumui naudojant Sutardo viskozimetrą. Buvo tiriamos vienodo vandens ir cemento santykio portlandcemenčio tešlos su cheminėmis įmaišomis ir be jų. Tyrimai atlikti naudojant rotacinį viskozimetrą Rheotest NH 4.1 su bendraašiais cilindrais. Nustatytas cheminių įmaišų portlandcemenčio tešlose veiksmingumas. Pastebėta, kad portlandcemenčio tešlų dinaminė klampa gali būti reguliuojama cheminėmis įmaišomis viso indukcinio hidratacijos periodo metu. Atlikus portlandcemenčio tešlų su cheminėmis įmaišomis ir be jų tyrimų rezultatų regresinę analizę, gautos empirinės lygtys.

The Effect of Fluorine on the Viscosity and Crystallization of Lithium Aluminosilicate Glasses

Lithium aluminosilicate glasses have high viscosities, resulting in high melting temperatures and processing temperatures. In this study, F was added to the LAS glasses to reduce the melting temperature and viscosity for float process. The effects of fluorine content on the viscosity and crystallization of the parent glasses were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential thermal analysis (DTA) and rotation viscometer. It was found that the addition of F was useful in reducing the melting temperature and viscosity. The main crystalline phase of resulting glass-ceramics was β-spodumene. The activation energy (E) of LAS glasses was decreased from 460.3 KJ/mol to 417.7 KJ/mol with the addition of 2.63 wt% F, which accelerated the crystallization and enhanced the crystallinity of specimens.

Effect of Aging on the High-Temperature Rheological Properties of SBS Modified Asphalt

the aging existing in use and construction of bituminous pavement will directly resulting in shortening of the pavement’s service life. It is provide the theoretical basis of the design and construction of the SBS modified asphalt mixture to analyze the influence of aging to the rheological property of SBS modified asphalt under high temperature. The testing for the rheological property of three kinds SBS modified asphalt under high temperature has been finished before and after the aging in construction by Brookfield DV Ⅱ+ type of rotation viscometer. The results indicated that viscosity will be increased and the sensitivity of SBS modified asphalt to viscosity will also be lowered along with increase of aging degree. The testing for the rheological property of three kinds of SBS modified asphalt has been finished before and after aging in usage period by the dynamic shear rheometer (DSR). The results shown that G* will be continually increased along with increase of aging degree and this is consistent with change of base asphalt. And this shown that the increase of G* can only come down to oxidation and aging of base asphalt contained in the modified asphalt and also, asphaltene in SBS modified asphalt will be changing in the mode same with that of base asphalt.

DILATANCY OF CEMENT SLURRIES WITH CHEMICAL ADMIXTURES

The results of experimental investigation of plasticising, air‐entraining and viscosity‐modifying admixtures with different chemical composition influence on rheological properties and dilatancy of cement slurries are presented in the article. Rheological properties of cement slurries were tested by a rotation viscometer with coaxial cylinder, at different gradients of velocity. Dilatancy of cement slurries was determined by the distortion of the rheological curve and index of dilatancy D was calculated according to proposed methods. The results of investigation show that the properties of liquid disperse medium of structural system influence slightly the dilatancy of cement slurries. Plasticising admixtures with a different chemical composition slightly increases but air-entraining and viscosity-modifying admixtures slightly reduces the dilatancy of cement slurries.