Definitions of Terms Related to Polymer Blends, Composites, and Multiphase Polymeric Materials, VII.1

Dokument definira pojmove uvriježene u području polimernih mješavina i kompozita, a odnosi se na mješavine komponenata različitog kemijskog sastava ili molekulske mase u kojima je polimer kontinuirana faza. Popratni su termodinamički opisi uglavnom ograničeni na binarne mješavine iako se načelno mogu proširiti i na višekomponentne sustave. Dokument je podijeljen u tri poglavlja. Prvim su definirani osnovni pojmovi polimernih mješavina, drugim oni koji se najčešće primjenjuju za opisivanje ponašanja faznih domena polimernih mješavina. U trećem poglavlju definirani su pojmovi uobičajeni pri opisima morfologija fazno-razdvojenih polimernih mješavina.The document defines the terms most commonly encountered in the field of polymer blends and composites. The scope has been limited to mixtures in which the components differ in chemical composition or molar mass and in which the continuous phase is polymeric. Incidental thermodynamic descriptions are mainly limited to binary mixtures although, in principle, they could be generalized to multicomponent mixtures. The document is organized into three sections. The first defines terms basic to the description of polymer mixtures. The second defines terms commonly encountered in descriptions of phase domain behavior of polymer mixtures. The third defines terms commonly encountered in the descriptions of the morphologies of phase-separated polymer mixtures

Definitions of Terms Related to Polymer Blends, Composites, and Multiphase Polymeric Materials, VII.1

Dokument definira pojmove uvriježene u području polimernih mješavina i kompozita, a odnosi se na mješavine komponenata različitog kemijskog sastava ili molekulske mase u kojima je polimer kontinuirana faza. Popratni su termodinamički opisi uglavnom ograničeni na binarne mješavine iako se načelno mogu proširiti i na višekomponentne sustave. Dokument je podijeljen u tri poglavlja. Prvim su definirani osnovni pojmovi polimernih mješavina, drugim oni koji se najčešće primjenjuju za opisivanje ponašanja faznih domena polimernih mješavina. U trećem poglavlju definirani su pojmovi uobičajeni pri opisima morfologija fazno-razdvojenih polimernih mješavina.The document defines the terms most commonly encountered in the field of polymer blends and composites. The scope has been limited to mixtures in which the components differ in chemical composition or molar mass and in which the continuous phase is polymeric. Incidental thermodynamic descriptions are mainly limited to binary mixtures although, in principle, they could be generalized to multicomponent mixtures. The document is organized into three sections. The first defines terms basic to the description of polymer mixtures. The second defines terms commonly encountered in descriptions of phase domain behavior of polymer mixtures. The third defines terms commonly encountered in the descriptions of the morphologies of phase-separated polymer mixtures

Nomenclature and Terminology of Polymers, IV. Definitions of Basic Terms Relating to Low-molar-mass and Polymer Liquid Crystals

Ovo je prvi objavljeni dokument IUPAC-ove Komisije za nomenklaturu makromolekula koji obraðuje specifično područje kapljevitih kristala. Zbog opseÞnosti je pripremljen u suradnji s Međunarodnom udrugom za kapljevite kristale. Dokumentom je definirano pojmovlje koje se odnosi na niskomolekulske kapljevite kristale i kapljevite kristalne polimere. Obuhvaća temeljne definicije pojmova koji su uvrijeÞeni u području kapljevitih kristala i polimernoj znanosti. Pojmovi su podijeljeni u pet poglavlja koja obraðuju: opæe definicije stanja kapljevitih kristala i mezomorfna stanja, vrste mezofaza, optièku teksturu i nepravilnosti kapljevitih kristala, fizikalne karakteristike (ukljuèujuæi elektro-optička i magnetno-optička svojstva), i na kraju kapljevite kristalne polimere. Odabrani se pojmovi najčešće rabe pri standardnim strukturnim, termièkim i elektro-optičkim karakterizacijama kapljevitih kristalnih materijala

Polymerization, Thermal Stability and Degradation Mechanism of (Meth)acryl-Dicyclohexylurea and (Meth)acryl-Diisopropylurea Copolymers with Styrene and α-Methylstyrene

U radu je opisan utjecaj dicikloheksiluree (DCU) i diizopropiluree (DiPrU), u bočnom lancu monomera na osnovi (met)akrilata, na kopolimerizaciju sa stirenom (St) i α-metilstirenom (α-MeSt), toplinsku stabilnost i mehanizam razgradnje priređenih kopolimera. Polimerizacija je provedena s dibenzoil-peroksidom (Bz2O2) u butanonu ili dioksanu pri 70 °C, do niske konverzije. Rezultati pokazuju izrazite razlike u početnoj brzini polimerizacije i svojstvima polimera akrilatnih i metakrilatnih monomera u ovisnosti o supstituentu u bočnom lancu. Dok N-akril-N,N--dicikloheksilurea (A-DCU) lako homopolimerizira i kopolimerizira sa St-om i α-MeSt-om, N-metakril-N,N-dicikloheksilurea (MA-DCU) ne homopolimerizira niti kopolimerizira s α-MeSt-om, ali kopolimerizira sa St-om iako sporije nego odgovarajući akrilni monomer. Rezultati istraživanja pokazuju da uvođenje diizopropiluree umjesto dicikloheksiluree u metakrilatnom monomeru također utječe na početnu brzinu polimerizacije. Naime, N-(met)akril-N,N--diizopropilurea (MA-DiPrU) ne homopolimerizira niti kopolimerizira s α-MeSt-om. Polimerizacija sa St-om je sporija u usporedbi s odgovarajućim monomerom koji sadrži DCU. Kopolimerizacija je statistička reakcija u kojoj je, neovisno o sastavu smjese komonomera, uvijek veći udjel St-a u kopolimeru. Toplinsko ponašanje svih polimera u osnovi je slično. Zagrijavanjem pri temperaturama od 100 °C - 450 °C razgrađuju se dvostupnjevitim mehanizmom. U prvom stupnju pri temperaturama od 180 °C - 250 °C dolazi do izdvajanja cikloheksilizocijanata (C6H11NCO), odnosno izopropilizocijanata (C3H7NCO). Čvrsti ostaci identificirani su kao kopolimeri N-(met)akril-cikloheksilamida (A-CHA, MA-CHA), odnosno N-(met)akril-izopropilamida (MA-iPrA) sa St-om ili α-MeSt-om. Stabilni su do 280 °C, a zatim se u jednom stupnju razgrađuju pri temperaturama od 280 °C - 450 °C.This paper describes the polymerization of N-acryl-N,N\u27-dicyclohexylurea (A-DCU), N-methacryl- N,N\u27-dicyclohexylurea (MA-DCU) and N-methacryl-N,N\u27-diisopropylurea (MA-DiPrU) monomers with styrene (St) and α-methylstyrene (α-MeSt), thermal stability and degradation mechanism of prepared copolymers. Free-radical initiated polymerization was performed to low conversion by using dibenzoyl peroxyde (Bz2O2) in butanone at 70 °C under nitrogen stream. It was found that the pendant group in (meth)acrylic monomers have high influence to the polymerization as well as to the copolymer properties. A-DCU readily homopolymerized and copolymerized with St and r1,A-DCU = 0.72 and r2,α-MeSt= 0.07, while MA-DCU does not homopolymerized or copolymerized with α-MeSt under the same conditions, but copolymerized with St to randomly composed copolymers after a long heating of comonomers. Copolymers A-DCU with α-MeSt prepared under different monomer-to monomer-ratios in the feed have random composition with an azeotropic point at ratio of 0.75 (A-DCU) to 0.25 (St). The initial rate of copolymerization indicates that the rate increases almost linearly with the increase of ratio of A-DCU in the comonomer feed. Reactivity ratios determined by the Kelen-Tüdös method are: r1,A-DCU = 0.72 and r2,α-MeSt = 0.07. Molar mass of copolymers increased from 8.5 to 30 (kg mol-1) when mole ratio of A-DCU to α-MeStin the feed increased from 0.1 to 0.9. Poly(A-DCU) and copolymers with α-MeSt decomposed by two-step mechanism. Under TGA (nitrogen,10 °C min-1) conditions in the first step between 180 °C and 250 °C a quantitative yield of cyclohexylisocyanate (C6H11NCO) separated by a decomposition of dicyclohexylurea (DCU). The thermally stable residue represented poly(acryl-cyclohexylamide), poly(A-CHA), and copolymer with α-MeSt, poly(A-CHA-co-α-MeSt). Glass transition temperature (Tg) of poly(A-DCU) was at 184 °C and Tg of residue, poly(A-CHA), was at 161 °C. Tg\u27s of the copolymers are higher for the copolymer with higher A-DCU content. Tg\u27s of residue are increased also when the content of A-CHA in copolymer increased. Copolymers of A-DCU with St have a random composition with an azeotropic point at a ratio of 0.73 (A-DCU) to 0.27 (St). The rate of copolymerization of A-DCU with St increases by the increase of A-DCU in the feed. The reactivity ratio are: r1,A-DCU = 0.80 and r2, St = 0.50. Molar mass of copolymer, prepared at equimolar ratio of monomers in the feed, is Mw = 78.6 kg/mol-1. These copolymers decompose in TGA conditions by two-step mechanism, which correspond to the mechanism explained for the copolymers of A-DCU with α-MeSt. MA-DCU copolymerized with St to randomly composed copolymers. The reactivity ratio determined by the KT method are: r1, MA-DCU= 0.18 and r2, St = 4.84. These values indicate that MA-DCU favors cross-propagation over homopolymerization, while St favors homopolymerization as opposite to cross-propagation. It also shows, that since St is more reactive than MA-DCU, copolymers contain a higher proportion of St units. It was found, that the rate of copolymerization of MA-DCU with St is slower than the rate of copolymerization of A-DCU with St, and that the rate of copolymerization decreases by increasing the amount of MA-DCU in the feed. Molar mass of copolymer prepared at equimolar ratios of comonomers in the feed is Mw=12 kg mol-1. Thermal properties of poly(MA-DCU-co-St) are similar to those previously described in the decomposition of poly[A-DCU-co-St(α-MeSt)]. The results have also shown quite a big influence of DiPrU group in MA-iPrU to the polymerization with St and α -MeSt. Namely, MA-DiPrU does not homopolymerized or copolymerized with α -MeSt, but can polymerize with St only after a long heating of comonomers at 70 °C. The copolymerization of MA-DiPrU with St is a statistical reaction in which regardless of monomer-tomonomer ratios in the feed, an excess of St was in the copolymer. The reactivity ratios (KT method) are: r1, MA-DiPrU = 0.39 and r2, St = 1.03. The obtained data indicate a monomer tendency to alternating structure. The initial rate of copolymerization decreases with increasing the content of MA-DiPrU monomer in the feed. Molar mass of all copolymers are approximately of the same values, Mw = 12 - 8 kg mol-1 and Mn = 8.7 - 6.2 kg mol-1. Thermal behavior of those copolymers correspond to the behavior of acrylic and methacrylic polymers containing DCU as pendant group. Namely, all copolymers decompose under TGA conditions by a two-step mechanism. In the first step between 180 °C and 250 °C isopropylisocyanate (C3H7NCO) separates by degradation of diisopropylurea (DiPrU) in the side chain. The thermally stable residue represents the copolymer of methacryl-isopropylamide with St, which decompose by one-step mechanism between 280 °C and 450 °C

Flow Improver Polymeric Additives for Crude Oil and Gas Condensate

U radu je dat pregled polimernih aditiva koji služe za sniženje tecišta i poboljšanje reoloških svojstava nafte i plinskog kondenzata. Opisane su temeljne vrste polimera koji se u te svrhe primjenjuju: polimeri na osnovi olefina, posebice etilena, kopolimeri vinil-acetata i alkil-fumarata, esteri akrilne i metakrilne kiseline te polimeri na osnovi anhidrida maleinske kiseline. Prikazan je mehanizam djelovanja aditiva i metode za utvrđivanje njihove djelotvornosti. Dio pregleda obuhvaća rezultate sinteze i primjene vlastitih aditiva za naftu i plinski kondenzat. Posebno je opisan utjecaj kemijske strukture i molekulske mase polimernih aditiva te njihove koncentracije na tecivost i viskoznost. Ispitivanja su provedena na uzorcima nafte s naftnih polja u INI, Števkovica, Obod i Đeletovci i plinsko-kondenzatnih polja Molve, Kalinovac, Stari Gradac i Gola te mađarskog polja Barcs. Rezultati pokazuju da na djelotvornost u primjeni bitno utječu vrste aditiva i nafte, odnosno plinskog kondenzata. Optimalni su rezultati postignuti primjenom aditiva na osnovi kopolimera dugolančanih estera metakrilne kiseline s vinil-karboksilnim kiselinama.This paper describes the problem of paraffin deposition during production, transportation and processing of crude oil and gas condensate. The troublesome paraffin stands for normal hydrocarbons ranging from approximately C18-C38, mixed with small amounts of branched paraffin, monocyclic paraffin, polycyclic paraffin, and aromatics. The amount of paraffin found in crude oils as described in the literature, varies from less than 1 to more than 50 percent. The solubility of paraffin depends on chemical composition, temperature and pressure. Paraffin precipitates at an equilibrium temperature and pressure defined as the cloud point. The paraffin deposits often begin on surfaces cooler than the liquid. The viscosity is increased by the presence of paraffin crystals and if the temperature is reduced sufficiently, the crude oil/gas condensate will become very viscous (pour point). The crude oil/gas condensate viscosity behaves in a Newtonian manner until wax crystals begin to form and, after lowering the temperature, behaves in a non-Newtonian manner. Many options are available to counter the problems caused by paraffin wax deposition. These include various mechanical, thermal and chemical means (for example, steam heating, blending with lighter cutter stocks and treating with chemical additives). A preferred option would be to use wax modifier additives, commonly known as pour point depressants. Crystal modifiers are copolymers from these groups: copolymers of ethylene vinyl acetate, poly alpha-olefins, alkyl fumarate- vinyl acetate copolymers of C18-through C22 methacrylates and copolymers of maleic anhydride esters. The mechanism of paraffin deposition and prevention is described. The additives modify the size and shape of the crystal and inhibit the formation of large wax crystal lattices. With efficient additives, crude oil/gas condensate behaves in a Newtonian manner at low temperature. A section of the paper describes the influence of chemical structure and molecular weight of the flow improver additives for crude oils and gas condensates prepared by the authors of this review article. The additives are based on methacrylic long chain alkyl ester homopolymers or copolymers with vinyl carboxylic acids or vinyl aromatic monomers. The quality of the prepared additives as pour point depressants and rheology improvers was proved by applying them to crude oil from INA fields Števkovica, Obod and Deletovci as well as gas condensate fields Molve, Kalinovac, Stari Gradac, Gola, and Hungarian gas condensate field Barcs. The best results were obtained with the copolymers of methacrylic long-chain alkyl esters with functional monomers