No abstract

On the basis of the reports from 2010 to 2018, the chemical structure, production methods and applications of polyurethane ionomers were reviewed. The paper presents ionogenic reagents and counterions responsible for the incorporation of anionic and cationic groups into polyurethane chains and the resulting physicochemical properties of these polymers. The most important applications of synthesized ionomers as a waterborne polyurethane, elastomer materials, biomaterials and materials for special applications (electronics, nanocomposites) were presented. Abbreviations PUPolyurethane PUI Polyurethane ionomer PUD Polyurethane dispersion WPU Waterborne polyurethane HMDI 4,4 0 -Methylene bis(cyclohexyl isocyanate) MDI 4,4 0 -Methylenebis(phenyl isocyanate) HDI 1,6-Hexamethylene diisocyanate IPDI Isophorone diisocyanate PTMO Polytetramethylene glycol PCD Polycarbonate diol POG Polyethylene glycol PPG Polypropylene glycol PCL Poly(e-caprolactone) diol PLA Polylactide diol PDMS Poly(dimethylsiloxane) DMPA 2,2-Bis(hydroxymethyl)propionic acid DMBA 2,2-Bis(hydroxymethyl)butyric acid

Taking advantage of the DSC method, general procedures were presented for qualitative and quantitative evaluation of the phase separation degree and the crystalline phase content in polyurethane elastomers with well-defined structures. Those elastomers were obtained not only in a typical one-step method but also in the prepolymer method with the use of urethane oligomers with controlled molecular weight distribution (MWD). Prepolymers with well defined chain structures and narrow distributions of their molecular weights (MWD) M w /M n ¼ 1.1-1.3 were produced in a multistage method, i.e., in step-by-step polyaddition of 2,4-and 2,6-TDI with polyoxyethylenediols or with polycaprolactonediols of varied molecular weights. Isocyanate oligomers obtained at individual stages were then crosslinked with triethanolamine, whereas hydroxyl-terminated oligomers were crosslinked with 4,4 0 ,4 00 -triphenylmethane triisocyanate (Desmodur RE). The obtained polyurethane elastomers were found to be characterized by the presence of five phases: soft phase consisted of flexible polyol-type segments, crystalline phase made of soft segments, crystalline and amorphous hard phase made of hard segments, and intermediate phase, which was a composition of the soft and hard segments. The polyurethanes obtained out of prepolymers with defined MWD were characterized by better phase separation of the soft segments and increased structural order inside the hard phase as well as by better thermal stability than polyurethanes obtained from the typical one-step method. The structural effects were also discussed on the thermal properties of the synthesized elastomers as analyzed by the TG and DTA methods.

No abstract

No abstract

Objective: We assessed the prognostic factors related to 10-year overall survival and disease-free survival in cervical cancer patients that underwent primary surgical protocols in 1 institution. Materials and Methods: A total of 102 patients with uterine cervical cancer at FIGO stages IA2-IIB that underwent a Piver type III radical hysterectomy and pelvic lymphadenectomy between 1998 and 2001 were included. Univariate and multivariate analyses of 10-year overall survival and 10-year disease-free survival were performed. Results: Univariate analysis revealed that only lymphovascular space invasion significantly affected 10-year overall survival (p = 0.04), but it had no effect on the 10-year disease-free survival rate. Multivariate analysis demonstrated that survival rates were significantly affected by FIGO stage (p = 0.02, 95% CI: 1.18-5.55, for 10-year overall survival; p = 0.03, 95% CI: 1.07-6.12, for 10-year disease-free survival) and metastases to the pelvic lymph nodes (p = 0.0005, 95% CI: 1.81-8.53, for 10-year overall survival; p = 0.01, 95% CI: 1.26-7.24, for 10-year disease-free survival). Conclusions: The only independent prognostic factors for 10-year survival rates in patients with cervical cancer at FIGO stages IA2-IIB were clinical stage and presence of metastases to the pelvic lymph nodes. The presence of lymphovascular space invasion adversely affected 10-year overall survival.

ARGET (activators regenerated by electron transfer) ATRP (atom transfer radical polymerization) has been successfully performed (in flasks fitted with rubber septa without the need for use of Schlenk line) in the presence of limited amount of air and with a very small (370 ppm) amount of copper catalyst together with an appropriate reducing agent Cu(0). Novelty of this work is that the poly(methyl methacrylate)-block-polyurethane-block-poly(methyl methacrylate) triblock copolymers were synthesized for the first time through ARGET ATRP, by using tertiary bromine-terminated polyurethane as a macroinitiator (MBP-PU-MBP), CuBr2 or CuCl2 as a catalyst and N,N,N',N",N"-pentamethyldiethylenetriamine (PMDETA) or 2,2'-bipyridine (Bpy) as a complexing agent. As the polymerization time increases, both the monomer conversion and ln([M]0/[M]) increased and the molecular weight of copolymer increases linearly with increasing conversion. Theoretical number-average molecular weight (Mn, th) of the tri-block copolymers was found to be comparable with number-average molecular weight determined by GPC analyses (Mn, GPC). These results indicate that the formation of the tri-block copolymers was through atom transfer radical polymerization mechanism. 1H and 13C NMR spectral methods were employed to confirm chemical structures of synthesized macroinitiator and tri-block copolymers. Mole percentage of PMMA in the tri-block copolymers was calculated using 1H NMR spectroscopy and was found to be comparable with the GPC results. Additionally, the studies of surface properties (confocal microscopy and SFE) of tri-block copolymer coatings confirmed the presence of MMA segments

The polarity of polyurethane coats was studied on the basis of the goniometric method for determination of wetting angle values, on the basis of calculated surface free energy (SFE) values by the van Oss–Good and Owens–Wendt methods, and on the basis of polarity measurements with the use of the 1H NMR spectra. Test polyurethanes were synthesised in the reaction of methylene diphenyl 4,4′-diisocyanate (MDI) or 3-izocyanatomethyl –3,5,5- trimethylcyclohexyl isocyanate (IPDI) and polyoxyethylene glycols or polyesters poly(ε-caprolactone) diols and poly(ethyleneadipate) diol with different molecular weights, and some diols as chain extenders, in dioxane. The type of raw material was found to significantly affect the phase structure of the obtained polyurethane elastomers and to control physical interactions within those structures, thus influencing the SFE values. Fundamental reduction in the SFE value of a coating below 28 mJ/m2 was achieved by the use of 2,2,3,3-tetrafluoro-1,4-butanediol as the urethane prepolymer chain extender.