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New Copolymers (new + copolymer)

Distribution by Scientific Domains

Polymers and Materials Science	80%

Selected Abstracts

A Self-Assembling Polythiophene Functionalised with a Cysteine Moiety

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 9 2003
Adele Mucci
Abstract A new copolymer bearing a cysteine moiety, designed for molecular interaction, metal-ion detection, and chiral recognition, was synthesised starting from the dibromo derivative of methyl N -(tert -butoxycarbonyl)- S -thien-3-ylcysteinate and distannylthiophene through a Stille coupling reaction. UV-vis spectroscopy, circular dichroism, NMR spectroscopy, and gel permeation chromatography analyses evidenced that this polymer is able to form self-assembling structures, through the formation of a hydrogen-bond network, not only in the solid state but also in solution. [source]

Toughening effects of poly(butylene terephthalate) with blocked isocyanate-functionalized poly(ethylene octene)

POLYMER INTERNATIONAL, Issue 8 2009
Ligang Yin
Abstract BACKGROUND: Blocked isocyanate-functionalized polyolefins have great potential for use in semicrystalline polymer blends to obtain toughened polymers. In this study, poly(butylene terephthalate) (PBT) was blended with allyl N -[2-methyl-4-(2-oxohexahydroazepine-1-carboxamido)phenyl] carbamate-functionalized poly(ethylene octene) (POE- g -AMPC). RESULTS: New peaks at 2272 and 1720 cm,1, corresponding to the stretching vibrations of NCO and the carbonyl of NHCON, respectively, in AMPC, appeared in the infrared spectrum of POE- g -AMPC. Both rheological and X-ray photoelectron spectroscopy results indicated a new copolymer was formed in the reactive blends. Compared to uncompatibilized PBT/POE blends, smaller dispersed particle sizes with narrower distribution were found in the compatibilized PBT/POE- g -AMPC blends. There was a marked increase in impact strength by about 10-fold over that of PBT/POE blends with the same rubber content and almost 30-fold higher than that of pure PBT when the POE- g -AMPC content was 25 wt%. CONCLUSION: The blocked isocyanate-functionalized POE is an effective toughener for semicrystalline polymers. Super-toughened PBT blends can be obtained when the POE- g -AMPC content is equal to or more than 15 wt%. Copyright © 2009 Society of Chemical Industry [source]

Conditioning polymers in today's shampoo formulations , efficacy, mechanism and test methods

INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2000
Hössel
Synopsis Today's shampoo formulations are beyond the stage of pure cleansing of the hair. Additional benefits are expected, e.g. conditioning, smoothing of the hair surface, improvement of combability and lather creaminess. Cationic polymers play an important role in providing many of those features. Therefore, within the last few years their use in shampoos has increased greatly. In the only last two decades, shampoo designation has gradually changed from ,2-in-1' to ,3-in-1' and then to ,multifunctional', as at present. The consumer demands products which live up to their promises. Modern shampoos contain a wide variety of ingredients such as co-surfactants, vitamins and pro-vitamins, protein derivatives, silicones, natural-based plant extracts and other ,active ingredients', but there is still a need for conditioning polymers. The specific objective of this study is to assess the conditioning efficacy of cationic polymers and to investigate their mechanisms in a shampoo system. The investigations were carried out on formulations that contained sodium lauryl ether sulphate and different cationic polymers, e.g. Polyquaternium 7, 10, 11, cationic guar gum and Luviquat Care (Polyquaternium 44), a new branched copolymer of vinylpyrrolidone (VP) and quaternized vinylimidazolium salts (QVI). We used test methods relevant to the applications in question, such as combing force measurements, the feel of the hair and the creaminess of the lather, to assess the efficacy. Atomic force microscopy and electrokinetics (streaming potential) were used to detect polymer residues on treated hair. All the polymers under investigation improved the overall performance of the shampoo formulations. This was demonstrated by means of combing force measurements, sensorial tests and analytical methods, namely zeta potential measurement and atomic force microscopy. Polyquaternium 44 exhibited the best conditioning properties on wet hair without sacrificing removability or absence of build-up. The latter are the most striking weaknesses of cationic Guar Gum-based polymers. Polyquaternium 10 can also be removed from the hair after rinsing with anionic surfactant but it does not perform as well as Polyquaternium 44 in the fields of wet combability and sensorial criteria such as lather creaminess and feel of the hair. We postulate that the outstanding properties of Polyquaternium 44 as a conditioning agent for shampoos are due to its tailor-made ,branched' structure. There is a clear correlation between the molecular weight and the efficacy of the new copolymers of VP and QVI. Only cationic polymers with a very high molecular weight are effective as conditioners in shampoos based on anionic surfactants. Surprisingly, they do not have to have a high cationic charge. On the basis of all our results, our postulation is that the polymer residue which is responsible for conditioning does not form a flat layer on the hair. Rather, the polymer residue adsorbs with the few cationic moieties, while the uncharged part of the polymer forms loops, which are orientated away from the hair and which are responsible for the reduced friction between hairs. Résumé Les formulations actuelles de shampoing font plus qu'un simple nettoyage des cheveux. On en attend un intérêt supplémentaire, par exemple après-shampoing, lissage de la surface du cheveu, amélioration de la coiffabilité et aspect crémeux du savon. Les polymères cationiques jouent un rôle important dans l'apport de nombre de ces caractéristiques. Par conséquent, ces quelques dernières années leur utilisation a considérablement augmenté dans les shampoings. Dans les seules deux dernières décades, l'appellation du shampoing est progressivement passée de "2 en 1"à"3 en 1" puis ensuite à"multifonctionnel", comme actuellement. Le consommateur recherche des produits qui tiennent leurs promesses. Les shampoings modernes contiennent une grande diversité d'ingrédients tels que des co-tensioactifs, des vitamines et des provitamines, des dérivés de protéines, des silicones, des extraits à base de plantes naturelles et autres "ingrédients actifs", mais il existe toujours un besoin pour des polymères d'après shampoing. L'objectif spécifique de cette étude est d'évaluer l'efficacité comme après-shampoing de polymères cationiques et de rechercher leurs mécanismes dans le système de shampoing. Les recherches ont été menées sur des formulations qui contiennent du sulfate de lauryl éther sodium et différents polymères cationiques, par exemple du Polyquaternium 7, 10, 11, de la gomme de guar cationique et du Luviquat Care (Polyquaternium 44), un nouveau copolymère ramifié de vinylpyrrolidone (VP) et de sels quaternaires de vinylimidazolium (QVI). Nous avons utilisé les procédés de contrôle appropriées aux applications en question, tels que les mesures de force de coiffage, le toucher du cheveu et l'aspect crémeux du savon, pour évaluer l'efficacité. La microscopie atomique et l'électrocinétique (potentiel d'écoulement) ont été utilisées pour détecter les résidus de polymère sur le cheveu traité. Tous les polymères étudiés améliorent le comportement global des formulations de shampoing. Ceci est démontré au moyen des mesures de force de coiffage, des tests sensoriels et des méthodes analytiques, en l'occurrence la mesure du potentiel zêta et la microscopie atomique. Le Polyquaternium 44 présente les meilleures propriétés d'après-shampoing sur cheveu mouillé sans diminuer sa capacité d'élimination ou l'absence d'accumulation. Ces dernières sont les faiblesses les plus frappantes des polymères à base de gomme de guar cationique. Le Polyquaternium 10 peut aussi être éliminé du cheveu après rinçage avec un tensioactif anionique mais il ne se comporte pas aussi bien que le Polyquaternium 44 dans les domaines de la coiffabilitéà l'état mouillé et des critères sensoriels tels que l'aspect crémeux du savon et du toucher du cheveu. Nous supposons que les propriétés exceptionnelles du Polyquaternium 44 comme agent après-shampoing pour shampoings sont dues à sa structure "ramifiée" conçue sur mesure. Il existe une corrélation claire entre le poids moléculaire et l'efficacité des nouveaux copolymères de VP et QVI. Seuls les polymères cationiques avec un poids moléculaire très élevé sont efficaces comme après shampoings dans des shampoings à base de tensioactifs anioniques. Etonnamment, ils n'ont pas besoin d'avoir une charge cationique élevée. Sur la base de tous nos résultats, notre hypothèse est que le fragment de polymère qui est responsable du traitement ne forme pas une couche plate sur le cheveu. Le fragment de polymère adsorbe plutôt les quelques fragments cationiques, tandis que la partie non chargée du polymère forme des boucles, qui sont orientées à l'extérieur du cheveu et qui sont responsables de la friction réduite entre les cheveux. [source]

The discovery of metallocene catalysts and their present state of the art

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 16 2004
Walter Kaminsky
Abstract Metallocene and other transition metal complexes activated by methylaluminoxane are highly active catalysts for the polymerization of olefins, diolefins, and styrene, which was discovered at the University of Hamburg about 25 years ago. These catalysts allow the synthesis of polymers with a highly defined microstructure, tacticity, and stereoregularity, as well as new copolymers with superior properties such as film clarity, tensile strength, and lower extractables. A better understanding of the mechanism of olefin polymerization leads to findings of other new single site catalysts. The development of the metallocene/MAO-catalysts from their discovery to their present state of the art is presented. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3911,3921, 2004 [source]

Synthesis and Characterization of New Types of Perylene Bisimide-Containing Conjugated Copolymers,

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 9 2005
Xiaorong He
Abstract Summary: Two new poly(perylene bisimide) polymers that contain biphenyl (PPery) and anthracene (PPeAn) groups at the bay position of perylene bisimide are designed and synthesized. The images of scanning and transmission electron microscopies for PPery and PPeAn show that both polymers form uniform nanoparticles. These copolymers emit red photoluminescence at around 640 nm with a relatively high photoluminescence quantum yield, 48% (in solution) for PPery and 68% (in solution) for PPeAn. Structures of the new copolymers synthesized here: PPery and PPeAn. [source]