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Characterization of the molar mass distribution (MMD) of poly (ether ether ketone) (PEEK) is very troublesome due to the insolubility of PEEK in common solvents. The solubility of PEEK may be substantially improved after its sulfonation. Sulfonated PEEK (SPEEK) was prepared by sulfonation of PEEK with 98% concentrated H2SO4 at room temperature. The presence of sulfonic acid group (-SO3H) in PEEK matrix was confirmed by nuclear magnetic resonance and Fourier transform infrared spectroscopy. The degree of sulfonation (DS similar to 95%) was determined by proton nuclear magnetic resonance in deuterated dimethyl sulfoxide and by thermal analysis methods. The equivalent molar mass and MMD of sulfonated PEEK was determined at 30 degrees C in three polar solvents (N,N-dimethylacetamide, N,N-dimethylformamide N-methyl-2-pyrollidone) in PS/DVB column using calibration with PMMA standards. A salt (LiBr) was added to the solvents for suppression of undesired interactions of analytes with the column packing. Moreover, the sulphonated PEEK was separated with size exclusion chromatography (SEC) coupled to a multi-angle light scattering (MALS) detector. It was found that the absolute average molar mass of SPEEK from the MALS detection is much closer to the value measured by SEC in N,N-dimethylacetamide +LiBr than the values determined in N,N-dimethylformamide and N-methyl-2-pyrollidone., Charakterizace distribuce molární hmotnosti PEEKu je velmi obtížná v důsledku jeho nerozpustnosti v běžných rozpouštědlech. Jeho rozpustnost může být zlepšena jeho sulfonací pomocí 98 % kyseliny sírové. Přítomnost sulfo skupin v PEEKu byla potvrzena pomocí NMR a IR spektroskopie. Stupeň sulfonace byl stanoven pomocí 1H NMR v deuterovaném DMSO a TGA metodou. Molární hmotnost sulfonovaného PEEKu byla stanovena pomocí SEC ve třech rozpouštědlech (N,N-dimethyl acetamid, N,N-dimethyl formamid, N-methyl pyrrolidon) pomocí PS/SDV kolon kalibrací pomocí PMMA standardů. LiBr byl přidán do mobilní fáze pro potlačení nežádoucích interakcí. Sulfonovaný PEEK byl též analyzován pomocí SEC s detektorem víceúhlového rozptylu světla (MALS). Bylo zjištěno, že absolutní molární hmotnost SPEEKu z MALS detektoru je o hodně bližší hodnotě stanovené kalibrací v N,N-dimethyl acetamidu než v ostatních dvou rozpouštědlech.

Facile monomer synthesis provided routes towards novel step-growth polymers for emerging applications. Adjustment of reaction conditions enabled green synthetic strategies, and promising scalability studies offered impetus for industrial funding. Engineering thermoplastics, such as linear polyetherimides (PEIs), had carefully targeted molecular weights for analysis of the effect of molecular weight and regiochemistry on the thermomechanical and rheological properties of PEIs. The design of linear, high performance PEIs comprising 3,3'- and 4,4'-bisphenol-A dianhydride (bis-DA) and m-phenylene diamine (mPD) provided an opportunity to elucidate the influence of dianhydride regiochemistry on thermomechanical and rheological properties. This unique pair of regioisomers allowed the tuning of the thermal and rheological properties for high glass transition temperature polyimides for engineering applications. The selection of the dianhydride regioisomer influenced the weight loss profile, entanglement molecular weight, glass transition temperature (Tg), tensile strain-at-break, zero-shear melt viscosity, average hole-size free volume, and the plateau modulus prior to viscous flow during dynamic mechanical analysis (DMA). The 3,3'-PEI composition interestingly exhibited a ~20 °C higher Tg than the corresponding 4,4'-PEI analog. Moreover, melt rheological analysis revealed a two-fold increase in Me for 3,3'-PEI, which pointed to the origin of the differences in mechanical and rheological properties as a function of PEI backbone geometry. The frequently studied 4,4'-PEI exhibited exceptional thermal, mechanical, and rheological properties, yet the 3,3'-PEI regioisomer lacked significant study in the industrial and academic sectors due to its 'inferior' properties, namely poor mechanical properties. Introduction of long-chain branching (LCB) into PEIs provided a unique comparison between a commercially relevant PEI (Ultem® 1000) and a regioisomer infrequently found in the lite

Although polyamide 6 (PA6) obtained from e-caprolactame (CL) is an engineering polymer with outstanding properties used in sliding applications, it exhibits low impact strength and high water absorption. Those are some of the reasons why copolymerization between CL and laurolactame (LL) is desired. In this work, copolymers from 0–100 wt% LL are prepared to evaluate crystallinity, melting behavior, tensile properties and those properties are correlated with coefficient of friction. Experimental results show that PA6 (0 wt%) crystallinity and elasticity modulus are higher than those obtained from 100 wt%LL (PA12), but friction coefficient in PA6 is lower than that of PA12. While with 60 wt% LL crystallinity and elastic modulus reach a minimum value, with 350% elongation and coefficient of friction they register a maximum value. Our results suggest that crystallinity and elastic modulus are opposed to coefficient of friction. The absence of hydrogen bonds produces irregularities in the chain, reducing the crystal formation; such behavior is a consequence of copolymerization. Our findings will help to customize copolyamide, modulate the response between mechanical properties and friction behavior, as well as evaluate when it is necessary to add lubricants in the copolymer formulations. © 2016 Elsevier B.V.

Elastic protein-based polymers have been synthesized. These are solid materials having been cross-linked by gamma-ray irradiation. Three of these samples have been measured. The results show that their elastic properties are different from traditional rubbers and polyurethanes. Typical absorbent materials have loss factors that rise with increase in frequency and a shear modulus that is relatively flat with frequency. On the other hand, the protein-based polymers have large loss factors at low frequencies, have loss factor that decrease with frequency, and have shear modulus that sharply increase at the high frequency end. These results demonstrate that these new materials hold great promise in their application as materials for broad band anechoic coatings for ships and submarines.