176 research outputs found

    Thermal Conductivity of Polymer/Nano-filler Blends

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    To improve the thermal conductivity of an ethylene vinyl acetate copolymer, Elvax 260 was compounded with three carbon based nano-fillers. Multiwalled carbon nanotubes (MWCNT), vapor grown carbon nanofibers (CNF) and expanded graphite (EG) were investigated. In an attempt to improve compatibility between the Elvax and nanofillers, MWCNTs and EGs were modified through non covalent and covalent attachment of alkyl groups. Ribbons were extruded to form samples in which the nanofillers were aligned, and samples were also fabricated by compression molding in which the nano-fillers were randomly oriented. The thermal properties were evaluated by DSC and TGA, and mechanical properties of the aligned samples were determined by tensile testing. The degree of dispersion and alignment of the nanoparticles were investigated using high-resolution scanning electron microscopy. Thermal conductivity measurements were performed using a Nanoflash technique. The thermal conductivity of the samples was measured in both the direction of alignment as well as perpendicular to that direction. The results of this study will be presented

    Thermal Conductivity of Polyimide/Nanofiller Blends

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    In efforts to improve the thermal conductivity of Ultem(TM) 1000, it was compounded with three carbon based nano-fillers. Multiwalled carbon nanotubes (MWCNT), vapor grown carbon nanofibers (CNF) and expanded graphite (EG) were investigated. Ribbons were extruded to form samples in which the nano-fillers were aligned. Samples were also fabricated by compression molding in which the nano-fillers were randomly oriented. The thermal properties were evaluated by DSC and TGA, and the mechanical properties of the aligned samples were determined by tensile testing. The degree of dispersion and alignment of the nanoparticles were investigated with high-resolution scanning electron microscopy. The thermal conductivity of the samples was measured in both the direction of alignment as well as perpendicular to that direction using the Nanoflash technique. The results of this study will be presented

    Thermal Conductivity of Ultem(TradeMark)/Carbon Nanofiller Blends

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    In an effort to improve polymer thermal conductivity (TC), Ultem(TradeMark) 1000 was compounded with nano-fillers of carbon allotropes. Ultem(TradeMark) 1000 was selected since it is both solution and melt processable. As-received and modified multiwalled carbon nanotubes (MWCNTs), vapor grown carbon nanofibers (CNF) and expanded graphite (EG) were investigated. MWCNTs were modified by functionalizing the surface through oxidization with concentrated acids, mixing with an alkyl bromide, and addition of alkyl and phosphorus compounds after initial treatment with n-butyl lithium. Functionalization was performed to improve the TC compatibility between the resin and MWCNTs. It was postulated that this may provide an improved interface between the MWCNT and the polymer which would result in enhanced TC. The nano-fillers were mixed with Ultem(TradeMark) 1000 in the melt and in solution at concentrations ranging from 5 to 40 wt%. Ribbons were extruded from the blends to form samples where the nano-fillers were aligned to some degree in the extrusion direction. Samples were also fabricated by compression molding resulting in random orientation of the nano-fillers. Thermal properties of the samples were evaluated by Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analyzer (TGA). Tensile properties of aligned samples were determined at room temperature. The specimens were cut from the ribbons in the extrusion direction; hence the nano-fillers are somewhat aligned in the direction of stress. Typically it was observed that melt mixed samples exhibited superior mechanical properties compared to solution mixed samples. As expected, increased filler loading led to increased modulus and decreased elongation with respect to the neat polymer. The degree of dispersion and alignment of the nano-fillers was determined by high-resolution scanning electron microscopy (HRSEM). HRSEM of the ribbons revealed that the MWCNTs and CNFs were predominantly aligned in the flow direction. The TC of the samples was measured using a Nanoflash(TradeMark) instrument. Since the MWCNTs and CNF are anisotropic, the TC was expected to be different in the longitudinal (parallel to the nanotube and fiber axis) and transverse (perpendicular to the nanotube and fiber axis) directions. The extruded ribbons provided samples for transverse TC measurements. However, to determine the TC in the longitudinal direction, the ribbons needed to be stacked and molded under 1.7 MPa and 270 C. Samples were then obtained by cutting the molded block with a diamond saw. The largest TC improvement was achieved for aligned samples when the measurement was performed in the direction of MWCNT and CNF alignment (i.e. longitudinal axis). Unaligned samples also showed a significant improvement in TC and may be potentially useful in applications when it is not possible to align the nano-filler. The results of this study will be presented

    Thermal Conductivity of Polyimide/Carbon Nanofiller Blends

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    In efforts to improve the thermal conductivity (TC) of Ultem(TM) 1000, it was compounded with three carbon based nano-fillers. Multiwalled carbon nanotubes (MWCNT), vapor grown carbon nanofibers (CNF) and expanded graphite (EG) were investigated. Ribbons were extruded to form samples in which the nano-fillers were aligned. Samples were also fabricated by compression molding in which the nano-fillers were randomly oriented. The thermal properties were evaluated by DSC and TGA, and the mechanical properties of the aligned samples were determined by tensile testing. The degree of dispersion and alignment of the nanoparticles were investigated with high-resolution scanning electron microscopy. The thermal conductivity of the samples was measured in both the direction of alignment as well as perpendicular to that direction using the Nanoflash technique. The results of this study will be presented

    Relative Impact of Pain and Fatigue on Work Productivity in Patients with Rheumatoid Arthritis from the RA-BEAM Baricitinib Trial

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    Introduction To explore the relationship of pain and fatigue with daily activity and work productivity in rheumatoid arthritis (RA) patients from the baricitinib clinical trial, RA-BEAM. Methods In RA-BEAM, a double-blind phase 3 study, patients were randomized 3:3:2 to placebo (n = 488), baricitinib 4 mg once daily (n = 487), or adalimumab 40 mg biweekly (n = 330) with background methotrexate. The Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) measured fatigue and the pain visual analog scale (0–100 mm) assessed pain. Work Productivity and Activity Impairment Questionnaire-RA measured daily activity and work productivity. At weeks 12 and 24, pain was assessed using pain reduction (< 30%, 30% to < 50%, ≥ 50%) and overall pain score; clinically relevant FACIT-F changes were assessed by values < 3.56 and ≥ 3.56 and the FACIT-F normative value score (< 40.1, ≥ 40.1). Pairwise comparisons between pain/fatigue reduction groups were assessed using ANCOVA with pooled data on daily activity and work productivity. A mediator analysis with pain, fatigue, and disease activity measured their contribution to daily activity and work productivity. Data were pooled from all patients for most analyses, and baricitinib-treated patients were assessed as a sensitivity analysis. Results Reductions in pain (≥ 50%) and fatigue (≥ 3.56) had significant (p ≤ 0.001) effects on daily activity and work productivity improvement at weeks 12 and 24. Reductions in pain, fatigue, and disease activity accounted for most of the improvements in daily activity and work productivity. At the lowest levels of remaining pain (≤ 10 mm) at weeks 12 and 24, however, fatigue did not appear to impact work productivity. Similar trends were observed with baricitinib-treated patients. Conclusions Reductions in pain and fatigue were associated with improved daily activity and work productivity for all RA patients and for baricitinib-treated patients in RA-BEAM

    Vinorelbine alternating oral and intravenous plus epirubicin in first-line therapy of metastatic breast cancer: results of a multicentre phase II study

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    The combination of intravenous (i.v.) vinorelbine and epirubicin is highly active in the treatment of metastatic breast cancer (MBC). In an effort to improve patient convenience, we investigated a regimen alternating i.v. and oral vinorelbine in combination with epirubicin as first-line chemotherapy of patients with MBC. In all, 49 patients with MBC received, as first-line treatment, a combination regimen consisting of i.v. vinorelbine 25 mg m−2 plus epirubicin 90 mg m−2 given on day 1, and oral vinorelbine 60 mg m−2 on day 8 (or day 15 if neutrophils <1500 mm−3) every 3 weeks, in an open-label, multicentre phase II study. Treatment was to be repeated for a maximum of six cycles. The study population had a median age of 55 years, half of the patients had received prior adjuvant chemotherapy and 86% presented a visceral involvement. In all, 25 responses were documented and validated by an independent panel review, yielding response rates of 51% (95% CI: 36–66) in the 49 enrolled patients and 54.5% (95% CI: 39–70) in the 44 evaluable patients. Median durations of progression-free survival and survival were 8 and 20 months, respectively. Neutropenia was the main dose-limiting toxicity, but complications were uncommon, four patients having experienced febrile neutropenia and six having developed neutropenic infection. Other frequently reported adverse events included stomatitis, nausea and vomiting, which were rarely severe. No toxic death was reported. Among patients who received six cycles, global score of quality of life remained stable. This regimen alternating oral and i.v. vinorelbine in combination with epirubicin is effective and safe. Oral vinorelbine on day 8 offers greater convenience to the patient, and decreases the need for i.v. injection and reduces time spent in hospital. Therefore, oral vinorelbine is a convenient alternative to the i.v. form in combination regimens commonly used to treat MBC

    First-line high-dose sequential chemotherapy with rG-CSF and repeated blood stem cell transplantation in untreated inflammatory breast cancer: toxicity and response (PEGASE 02 trial)

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    Despite the generalization of induction chemotherapy and a better outcome for chemosensitive diseases, the prognosis of inflammatory breast cancer (IBC) is still poor. In this work, we evaluate response and toxicity of high-dose sequential chemotherapy with repeated blood stem cell (BSC) transplantation administered as initial treatment in 100 women with non-metastatic IBC. Ninety-five patients (five patients were evaluated as non-eligible) of median age 46 years (range 26–56) received four cycles of chemotherapy associating: cyclophosphamide (C) 6 g m−2 – doxorubicin (D) 75 mg m−2 cycle 1, C: 3 g m−2 – D: 75 mg m−2 cycle 2, C: 3 g m−2 – D: 75 mg m−2 – 5 FU 2500 mg m−2 cycle 3 and 4. BSC were collected after cycle 1 or 2 and reinfused after cycle 3 and 4. rG-CSF was administered after the four cycles. Mastectomy and radiotherapy were planned after chemotherapy completion. Pathological response was considered as the first end point of this trial. A total of 366 cycles of chemotherapy were administered. Eighty-seven patients completed the four cycles and relative dose intensity was respectively 0.97 (range 0.4–1.04) and 0.96 (range 0.25–1.05) for C and D. Main toxicity was haematological with febrile neutropenia ranging from 26% to 51% of cycles; one death occurred during aplasia. Clinical response rate was 90% ± 6%. Eighty-six patients underwent mastectomy in a median of 3.5 months (range 3–9) after the first cycle of chemotherapy; pathological complete response rate in breast was 32% ± 10%. All patients were eligible to receive additional radiotherapy. High-dose chemotherapy with repeated BSC transplantation is feasible with acceptable toxicity in IBC. Pathological response rate is encouraging but has to be confirmed by final outcome. © 1999 Cancer Research Campaig
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