252,614 research outputs found
Effect of the reactional variables on the synthesis of a functionalized biodegradable polymer: PCL-g-MA
No full textABSTRACT Poly (ɛ-caprolactone) (PCL) is a biodegradable synthetic thermoplastic that has been the focus of studies on new "green polymers", due mainly to its good mechanical properties, which makes it competitive among other conventional polymers and biopolymers, such as, Poly(lactic acid) (PLA) and Poly(hydroxybutyrene) (PHB). The objective of this work was the grafting of maleic anhydride (MA) reactive groups in PCL for the production of a functional biodegradable polymer. The grafting synthesis of the maleic anhydride in the PCL occurred in an internal lab mixer, using concentrations of 2.5 and 5.0% MA and 0.3 and 0.5% of the dicumyl peroxide initiator (DCP) at two temperatures of process, 110°C and 160°C. The methodology of factorial planning 23 was used to optimize the experiments, as well as to evaluate the efficiency of the reaction conditions employed for PCL functionalization. The results indicated that maleic anhydride was grafted onto PCL using the dicumyl peroxide initiator. The percentage of graphitized maleic anhydride (% gMA) was obtained by titration and confirmed by Fourier Transform Infra-Red (FTIR). Through the obtained results it can be inferred that higher content (5.0%) of MA positively favored the grafting. However, over certain amount, a saturation of the system may occur and the tendency is for recombination.</p
Compatibilization of recycled polypropylene and recycled poly (ethylene terephthalate) blends with SEBS-g-MA
No full textAbstract The compatibilization of recycled PP/PET blend with high and low concentration (20 and 5 phr) of elastomer functionalized by maleic anhydride (SEBS-g-MA) was achieved. Recycled polypropylene from plastic industry and recycled PET from post-consumer bottles was used. PP/PET blends: 80:20 w/w, 50:50 w/w and 20:80 w/w were prepared in an internal mixer for mechanical properties, thermal properties, morphology and rheological properties. SEBS-g-MA promoted compatibilization of the PP/PET blends and improved their properties. With an increasing compatibilization level, the refinement of morphology was observed in the PET rich blend. Compatibilized blends showed negative deviation in the PET glass transition temperature related to neat PET, demonstrating that compatibilization was very successful. PET crystallization was accelerated in the blends due to PP presence that enhanced nucleation. It was found that the 50/50/20 blend showed huge potential for textile fiber application and that of 80/20/20 showed more intermediary properties than neat polymers.</div
Ma payse : mazurka [pour piano] / par Berthum ; [ill. par] G. Vaccon
No full textTitre uniforme : Berthum, G. (18..-1926 ; compositeur). Compositeur. [Ma payse. Piano]Mazurkas (piano) -- +* 1800......- 1899......+:19e siècle:Piano, Musique de -- +* 1800......- 1899......+:19e siècle
Numerical simulation of performance of concrete-filled FRP tubes under impact loading
No full textC. Wu, T. Ozbakkaloglu, G. Ma and Z. Y. Huanghttp://www.rpsonline.com.sg/proceedings/9789810844554/html/tp.htm
Letter re: Ma and Pa Ferguson
No full textLetter from T. G. Cooke of the Perfect Voice Institute to Amon Carter offering voice lessons with the following handwritten note, "Dear Amon: Perhaps if you will take this course "Ma" and "Pa" would not object to your shouting
Herbe pincte : codice MA 592 della Biblioteca civica di Bergamo
No full textStudio linguistico e glossario del codice MA 592 della Biblioteca “Angelo Mai” di Bergamo, che contiene il volgarizzamento del "De viribus herbarum" di Macer Floridus, illustrato da Antonio Guarnerino
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
La dimensione apostolica della Chiesa domestica
No full textLa famiglia è non solo cellula fondamentale della società, ma soggetto ecclesiale. Come Chiesa domestica ha una identità e missione nella comunità, di cui è necessario ancor oggi comprendere la natura, i fondamenti e le implicazioni sul piano pastorale e sociale
Evaluation of the effect of compatibilizing agent (PP-g-MA) on PP/Thermoplastic starch blends
No full textABSTRACT The growing waste of plastics in the environment coupled with concerns about future oil shortages has increased interest in biodegradable polymers such as starch. In recent years, starch has been used in blends with different synthetic polymers. Such blends have been compatibilized by the use of compatibilizing agents of the copolymer type. In this study, the morphological, mechanical and thermal properties of polypropylene (PP)/thermoplastic starch (TPS) blends obtained in the presence of the compatibilizing agent (PP-g-MA) were evaluated. The thermoplastic starch was obtained in a single screw extruder with 20% (mass/mass) of glycerol used as plasticizer. PP/TPS blends were prepared by melt mixing in a co-rotating twin-screw extruder. The concentration of the compatibilizing agent was 3, 5 and 7% (mass/mass). The morphology of the blends was evaluated by scanning electron microscopy. The results showed a significant reduction of the dispersed starch phase with the addition of the PP-g-MA. The blends obtained in the presence of PP-g-MA showed a more homogeneous distribution of the starch phase in the PP matrix. The results obtained with the tensile tests showed that the elastic modulus of PP undergoes a slight increase with the addition of the starch and the compatibilizer. The tensile strength of the PP was not significantly affected. However, there was a significant decrease of the elongation at break with the incorporation of starch. The starch incorporated in the PP matrix led to a significant increase in the impact strength of the final material. However, with the addition of PP-g-MA to the PP/TPS blend, the impact strength falls. This result can be attributed to the reduction of the starch phase in the PP matrix. The thermal stability of the PP/TPS blends was slightly increased with the incorporation of the compatibilizing agent. The materials obtained can be used instead of PP.</p
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