Characterization of the effects of compressed gas annealing on semicrystalline polymers

The effects of annealing semicrystalline polymers in the presence of plasticizing agents is an area of considerable current interest, given the potential to modify the degree and nature of crystallinity. These effects were studied for two semicrystalline polymers, custom-synthesized methyl-substituted poly(aryl ether ether ketone) (MePEEK) and industrial-grade poly(ethylene terephthalate) (PET). Small-angle X-ray scattering (SAXS) was used to characterize the microstructure of both amorphous and preannealed materials. Differential scanning calorimetry (DSC), wide-angle X-ray scattering, and density measurements were also performed for the PET samples, and reference is made to similar analysis work done for MePEEK. A distinct morphological effect could be identified from SAXS measurements of MePEEK annealed in a stepwise fashion in the presence of high-pressure CO\u2082 with the polar cosolvent CH\u2083OH. This result was absent in MePEEK similarly annealed in air and supports earlier DSC measurements. A very different morphological effect of pressure alone was observed in PET annealed in pure CO\u2082 (170 and 510 atm) at a temperature of 150 \ub0C, well above the glass transition.Peer reviewed: YesNRC publication: Ye

Influence of clay content and amount of organic modifiers on morphology and pervaporation performance of EVA/clay nanocomposites

Poly(ethylene-co-vinyl acetate)/organically modified clay nanocomposites were prepared using different clay loadings and by varying the amount of organic modifier. The morphology of the nanocomposites was investigated using small-angle X-ray scattering (SAXS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). SAXS results displayed intercalation of polymeric chains between the silicate layers in all the cases. The interlayer distance varies slightly between the series. TEM images showed a better dispersion of the clay platelets at lower loading for both series of samples. The pervaporation performances of membranes were analyzed using a chloroform/acetone mixture. Membranes displayed high selectivity. The influence of feed composition on pervaporation was analyzed. The nanoclay content and the influence of free volume on pervaporation performance were also investigated in detail. A drop in selectivity and an increase in permeation rate were observed at higher clay loadings

Swelling transition of a clay induced by heating

-Clays are of paramount importance for soil stability, but also in applications ranging from oil recovery to composites and hydrogels. Generically, clays are divided into two subclasses: macroscopically swelling, ‘active’ clays that have the capacity for taking up large amounts of water to form stable gels, and ‘passive’ or non-swelling clays; the former stabilize soils whereas the latter are known to lead to landslides. However, it has been unclear so far what mechanisms underlie clay swelling. Here, we report the first observation of a temperature-induced transition from a passive to an active, swelling clay. We propose a simple description of the swelling transition; while net attractive interactions are dominant at low temperatures so that the clay particles remain attached to each other in stacks, at higher temperatures it is energetically favourable for the clay to swell due to the entropy that is gained by counterions which are liberated during swelling

A Multitechnique Study of Structure and Dynamics of Polyfluorene Cast Films and the Influence on Their Photoluminescence

This article describes the microstructure and dynamics in the solid state of polyfluorene-based polymers, poly(9,)-dioctylfluorenyl-2,7-diyl) (PFO), a semicrystalline polymer, and poly [(9,9-dioctyl- 2,7-divinylene-fluorenylene)-alt-co-{2-methoxy-5-(2-ethyl-hexyloxy)- 1,4-phenylene vinylene}, a copolymer with mesomorphic phase properties. These Structures were determined by wide-angle X-ray scattering (WAXS) measurements, Assuming a packing model for the copolymer structure, where the planes of the phenyl rings are stacked and separated by an average distance of similar to 4.5 angstrom and laterally spaced by about similar to 16 angstrom, we followed the evolution of these distances as a function of temperature using WAXS and associated the changes observed to the polymer relaxation processes identified by dynamical mechanical thermal analysis. Specific molecular motions were studied by solid-state nuclear magnetic resonance. The onset of the side-chain motion at about 213 K (beta-relaxation) produced a small increase in the lateral spacing and in the stacking distance of the phenyl rings in them aggregated Structures, Besides, at about 383 K (alpha-relaxation) there occurs a significant increase in the amplitude of the torsion motion in the backbone, producing a greater increase in the stacking distance of the phenyl rings. Similar results were observed in the semicrystalline phase of PFO, but in this case the presence of the crystalline structure affects considerably the overall dynamics, which tends to be more hindered. Put together, Our data explain many features of the temperature dependence of the photoluminescence of these two polymers.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESPCNPqConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)MCT/INEOMinistério da Ciência, Tecnologia e Inovação do Brasil (MCTI)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)CAPESBrazilian Synchrotron Light Laboratory (LNLS)[D02ASAXS2]Brazilian Synchrotron Light Laboratory (LNLS)Brazilian Synchrotron Light Laboratory (LNLS)Brazilian Synchrotron Light Laboratory (LNLS)[D11A-SASX5379

Swelling transition of a clay induced by heating

Clays are of paramount importance for soil stability, but also in applications ranging from oil recovery to composites and hydrogels. Generically, clays are divided into two subclasses: macroscopically swelling, ‘active’ clays that have the capacity for taking up large amounts of water to form stable gels, and ‘passive’ or non-swelling clays; the former stabilize soils whereas the latter are known to lead to landslides. However, it has been unclear so far what mechanisms underlie clay swelling. Here, we report the first observation of a temperature-induced transition from a passive to an active, swelling clay. We propose a simple description of the swelling transition; while net attractive interactions are dominant at low temperatures so that the clay particles remain attached to each other in stacks, at higher temperatures it is energetically favourable for the clay to swell due to the entropy that is gained by counterions which are liberated during swelling

Proportionaaliventtiilien elinkaaren analyysi

TIIVISTELMÄ Kemi-Tornion ammattikorkeakoulu, Tekniikan yksikkö Koulutusohjelma Sähkötekniikka Opinnäytetyön tekijä Mikko Aarni Opinnäytetyön nimi Proportionaaliventtiilien elinkaaren analyysi Työn laji Opinnäytetyö päiväys 29.3.2011 sivumäärä 56 + 5 liitesivua Opinnäytetyön ohjaaja DI Tuomas Pussila Yritys Outokumpu Oyj Yrityksen yhteyshenkilö/valvoja Insinööri Sauli Kiiskilä Tämä opinnäytetyö on tehty Outokumpu Oyj:lle Tornion tehtaiden kylmävalssaamolle. Kylmävalssaamolta työn valvojana toimi kunnossapitoinsinööri Sauli Kiiskilä. Työssä keskitytään tehtaan kylmävalssaamossa esiin tulleen ongelman selvittämiseen. Laitekanta on osittain päässyt vanhentumaan, jolloin on syytä selvittää kaikkien tarpeellisten uusien korvaavien laitteiden saatavuus tarvittaessa. Samalla pyritään laatimaan menetelmä proportionaaliventtiilien käyttöiän määrittämiseksi. Tietoa voisi ehkä hyödyntää välttämättömien huoltoseisokkien yhteydessä, jolloin ehkä voisi vaihtaa myös lähiaikoina käyttöikänsä loppuun tulevat venttiilit ja siten välttyä linjan pysähtymiseltä kesken tuotantoprosessin vältettävissä olevan laiterikon takia. Kirjallisuusosassa kuvattiin tuotantoprosessia, hydrauliikan ja kunnossapidon perusteita sekä tuotantoyksikössä käytössä olevaa kunnossapitojärjestelmää. Kokeellisessa osassa tehtiin piirikaavioista saatujen tietojen perusteella taulukko, josta selviää positio, proportionaaliventtiilin tyyppi ja VT-ohjauskortti. Proportionaaliventtiilien tyyppitietojen tarkistaminen sekä täydentäminen suoritettiin kiertämällä kaikki tuotantolinjat läpi ja käymällä läpi jokaisen yksittäisen proportionaaliventtiilin tyyppi. Koska joitakin poikkeamia oli vuosien varrella tehtyjen huoltojen yhteydessä jostakin syystä merkintöihin tullut, saatettiin listat ajan tasalle. Päivitetyt tiedot merkittiin kunnossapitojärjestelmä Kutiin. Samassa yhteydessä luotiin Kutiin myös järjestelmä, jossa jokaisen proportinaaliventtiilin käyttöikä rekisteröitiin ja näin luotiin perusdata, josta voidaan myöhemmin määritellä keskimääräinen käyttöikä kullekin venttiilityypille. Asiasanat: automaatio, analyysi, dokumentointi, elinkaari.ABSTRACT Kemi-Tornio University of Applied Sciences, Technology Degree Programme Electrical Engineering Name Mikko Aarni Title The Life Cycle of the Proportional Valve Type of Study Bachelor’s Thesis Date 29 March 2011 Pages 57 + 5 appendices tai appendixes Instructor Instructor Tuomas Pussila, MSc, (Tech.) Company Outokumpu Oyj ContactPerson/Supervisor from Company Sauli Kiiskilä, MechEng Outokumpu Oyj This study is done at the coldrolling productionlines of the Outokumpu Tornio Works under the Supervisor Sauli Kiiskilä, MechEng Outokumpu Oyj. The purpose of the job was to make the life cycle analysis of the proportional valves on the HP-3-line and the prepairingline and update the register of the equipments. The outdated equipments should be found and prepaired to substitude by the corresponding equipments. At the literature part was described the production process, the basics of the hydraulics and the basics of the preventive maintenance and the actual maintenance system. At the working part of the study the table was created where the position, the type of the proportional valve and the VT-control card can be found. The table was controlled by checking all the individual valves in the production lines and the errors were prepaired. All the new data was put into the Maintenance System Kuti. At the same time the working time of all the individual proportional valves was observed and the data was created, where the average life time of the valves can be calculated after some months and years