17 documents found, page 1 of 2
Properties evaluation of semi-crystalline and amorphous polymers injected in AI...
Junkes,Rafael; Howarth,Janaina Lisi Leite; Becker,Daniela; Bond,DanielleABSTRACT >Injection molds can fail after a certain period of use, which may compromise the final part’s integrity and quality, but that can be solved using welding repair processes. This work aimed to investigate the influence of AISI P20 molds repaired by Gas Tungsten Arc Welding (GTAW) and Nd-YAG laser-welding processes on the properties of injection-molded parts with semi-crystalline (polypropylene) and amor...
Nano-rugosidade gerada em amostras de polímero PEAD através de plasma RF de N2/O2
Mezaroba,Cristiane; Becker,Daniela; Nahorny,Jacimar; Recco,Abel André Cândido; Fontana,Luis CesarRESUMO Filmes de polietileno de alta densidade (PEAD) foram tratados por plasma radiofrequência (RF) de N2/O2. Foi investigado o efeito da pressão do gás de trabalho N2/O2, do plasma, na texturização superficial do filme. O plasma gerado em baixa potência (20W) permite manter a amostra em baixa temperatura (T<40°C) durante o tratamento de superfície. Os resultados mostram que a rugosidade superficial, em escala...
Electrical and thermal properties of PLA/CNT composite films
Ceregatti,Thayara; Pecharki,Paloma; Pachekoski,Wagner M.; Becker,Daniela; Dalmolin,CarlaABSTRACT Conducting polymers presents many potential applications such as biosensors and biofuelcells. However, to be used in those devices, a thin film must be deposited onto a conducting and biocompatible substrate. In this work, carbon nanotubes (CNT) were mixed in a poly (lactic acid) - PLA - matrix with different compositions (from 0.25 to 5.0 %) in order to form conducting composites suitable to the depos...
Influence of mixing methods on the properties of high density polyethylene nano...
Brandenburg,Ricardo Fischer; Lepienski,Carlos Mauricio; Becker,Daniela; Coelho,Luiz Antonio FerreiraABSTRACT In this paper, nanocomposites with multiwalled carbon nanotubes (MWCNT) or graphene nanosheets were prepared using a high density polyethylene (HDPE) matrix. Two different processes were employed: a solution method and a melt mixing method. The crystallinity index of the HDPE showed similar levels in nanocomposites after the addition of carbon nanotubes. It can be seen that the preparation process modi...
Role of Cured Epoxy and Block Copolymer Addition in Mechanical and Thermal Prop...
Silva,Bruna Louise; Christoff,Bruno Guilherme; Lepienski,Carlos Mauricio; Cardoso,Eduardo Lenz; Coelho,Luiz Antônio; Becker,DanielaThis work aims to investigate the role of epoxy addition in high density polyethylene (HDPE) matrix. The block copolymer polyethylene-b-poly (ethylene glycol) (PEG-co-PE) was used as a compatibilizer. The samples were obtained by melt mixing using a torque rheometer. Instrumental nanoindentation was used to determine Young's modulus and nanohardness, thermal properties were analyzed by differential scanning cal...
Tuberculosis among prison staff in Rio Grande do Sul
Busatto,Caroline; Nunes,Luciana de Souza; Valim,Andréia Rosane de Moura; Valença,Mariana Soares; Krug,Suzane Frantz; Becker,DanielaABSTRACT Objective: to evaluate the risk of infection and illness caused by Mycobacterium tuberculosis among health care and security staff in prisons in two regions of Rio Grande do Sul (RS). Method: cross-sectional study involving prison staff. An interview and sputum smear microscopy and culture were performed. Latent infection was evaluated according to the result of the tuberculin test (TT), self-referred....
Influence of calcium carbonate and slip agent addition on linear medium density...
Baumer,Marina I.; Leite,Janaina L.; Becker,DanielaIn this paper, the influence of calcium carbonate and slip agent on linear medium density polyethylene (LMDPE) processed by rotational molding was evaluated. LMDPE was dry blended with different CaCO3 masterbatch ratios, erucamide slip agent and then extruded, micronized and rotomolded. The powder samples were characterized using MFI (Melting flow index), dry flow and bulk density. The characterization of rotom...
Influence of intercalation methods in properties of Clay and carbon nanotube an...
Silva,Bruna Louise; Nack,Fernanda Czerkies; Lepienski,Carlos Mauricio; Coelho,Luiz Antonio Ferreira; Becker,DanielaIn this work, nanocomposites with simultaneous dispersion of carbon nanotubes and clays in a high density polyethylene (HDPE) matrix were prepared. Two different processes of preparation were employed: solution or melt intercalation. Two different montmorillonite clays were used separately: a natural (MMT-Na) or an organoclay (MMT-30B) and it was used multiwalled carbon nanotubes (MWCNT). Thermal properties wer...
Glass fiber hybrid composites molded by RTM using a dispersion of carbon nanotu...
Sene,Tarcísio S.; Silva,Laís V. da; Amico,Sandro C.; Becker,Daniela; Ramirez,Alejandro Manzano; Coelho,Luiz A. F.Nanocomposites based on epoxy and a mixture of clays and multi-walled carbon nanotubes (MWCNT) were produced by casting, and also molded by RTM using glass fibers as reinforcement, yielding a hybrid multi-scale micro/nanocomposite material. Two types of montmorillonite clays were used, natural (MMT-Na) and organophilic (MMT-30B). Higher viscosity was obtained for the mixture with MMT-30B and it was observed tha...
Characterization of calcium carbonate obtained from oyster and mussel shells an...
Hamester,Michele Regina Rosa; Balzer,Palova Santos; Becker,DanielaThere is a high content of calcium carbonate in mussel and oyster shells, which can be used in the formulation of medicine, in construction or as filler in polymer materials. This work has as its main objective to obtain calcium carbonate from mussel and oyster shells and used as filler in polypropylene compared their properties with polypropylene and commercial calcium carbonate composites. The shellfish was m...