15 research outputs found
Fire and Forget! One‐Shot Synthesis and Characterization of Block‐Like Statistical Terpolymers via Living Anionic Polymerization
Alkaline sulphite anthraquinone pulping of caucasian spruce (Picea orientalis L.) chips with added sodium borohydride and ethanol
The study determined and compared the yield, viscosity, and chemical and physical properties of the pulps obtained as a result of Alkaline Sulfite–Anthraquinone(AS-AQ) pulping of Caucasian spruce wood with and without the addition of sodium borohydride (ASAB process) and ethanol (ASAE). It was found that the addition of ethanol to the AS-AQ pulping had a favourable influence on the screened yield and kappa number of the pulps. The addition of NaBH4 to the AS-AQ pulping in general also had a favourable influence on these pulps’ indices, provided that the amount added was not higher than 1–2% and the time of pulping was 180 mins. The higher yield of the ASAE pulps resulted from the higher retention of both cellulose and hemicelluloses, while the higher yield of ASAB pulps resulted from the higher retention of hemicelluloses and lignin. Regarding the AS-AQ pulping conditions,a distinct negative effect of modification on the viscosity of the pulps was observed in the case of the NaBH4 a additions to this pulping process. The viscosity reduction was, however, lower with extended pulping time. The static strength properties (tensile index and burst index) of the ASAB and ASAE pulps were in general lower than the AS-AQ pulps. In the case of the tear index, the tendency was similar.The addition of ethanol and especially NaBH4 to the AS-AQ pulping had a distinctly unfavourable influence on the whiteness and brightness of the pulps
THE PREVALANCE OF ATROPHIC GASTRITIS AND INTESTINAL METAPLASIA IN HELICOBACTER PYLORI GASTRITIS
ANTIMICROBIAL SUSCEPTIBILITY OF HELICOBACTER PYLORI: WHAT ARE THE RESISTANCE RATES FOR FIVE COMMONLY USED ANTIBIOTICS?
Regiospecific Radical Polymerization of Vinyl Methacrylate in the Presence of Lewis Acids into Soluble Polymers with Pendent Vinyl Ester Substituents
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Temperature-responsive properties and drug solubilization capacity of amphiphilic copolymers based on N-vinylpyrrolidone and vinyl propyl ether
A series of amphiphilic copolymers were synthesized by free-radical copolymerization of N-vinylpyrrolidone (NVP) with vinyl propyl ether (VPE), and the structure of the copolymers was characterized by elemental analysis and gel permeation chromatography. The reactivity of VPE in copolymerization was found to be significantly lower than the reactivity of NVP, which resulted in a decrease of copolymers’ yields and molecular weights with higher content of VPE in the feed mixture. An investigation of the behavior of the copolymers in aqueous solutions at different temperatures by dynamic light scattering revealed the presence of lower critical solution temperature, which depending on the content of VPE ranged within 23−38 °C. Aqueous solutions of these copolymers were studied by fluorescent spectroscopy with pyrene as a polarity probe to reveal the formation of hydrophobic domains. The copolymers were found to be useful for enhancing the solubility of riboflavin in water