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A thermodynamic scaling law for the relaxation times of complex liquids as a function of temperature and volume has been proposed in the literature: τ(T,V) = ƒ(TVγ), where γ is a material-dependent constant. We test this scaling for six materials, linear polystyrene, star polystyrene, two polycyanurate networks, poly(vinyl acetate), and poly(vinyl chloride), and compare the thermodynamic scaling to T - Tg scaling, where τ = ƒ(T - Tg). The thermodynamic scaling law successfully reduces the data for all of the samples; however, polymers with similar structures but different glass transition (Tg) and pressure-volume-temperature (PVT) behavior, i.e., the two polycyanurates, cannot be superposed unless the scaling law is normalized by TgVgγ. On the other hand, the T - Tg scaling successfully reduced data for all polymers, including those having similar microstructures. In addition, the T - Tg scaling is easier to implement since it does not require knowledge of the PVT behavior of the material. The relationship between TgVgγ/TVγ and T - Tg scaling is clarified and is found to be weakly dependent on pressure. [ABSTRACT FROM AUTHOR]

High aspect ratio multi-walled carbon nanotubes (MWCNTs) having an average length of 4.23 μm and an average diameter of 9.5 nm have been melt mixed with immiscible polystyrene/poly(methyl methacrylate) (PS/PMMA) blends in mass ratio 80:20 and 20:80, respectively. The carbon nanotubes (CNTs) reside in the PMMA phase, and length analysis after melt mixing indicates that when PMMA was the minor phase (20 wt%), little or no CNT breaking occurred during mixing. On the other hand, when PMMA was the major phase (80 wt%), the average length of the CNTs was reduced to 2.78 μm, approximately 70% of their original length. Mixing the CNTs with neat PMMA under the same mixing conditions resulted in a reduction in CNT length to 1.02 μm, only 24% of the original length. Electrical conductivity results show that less CNT breakage leads to a reduction by a factor of 2.5 in the electrical percolation threshold in the 20:80 PMMA/PS blend polymer, which is much larger than a simple volume fraction argument would suggest. This article shows for the first time that relatively long MWCNTs break less in polymer blends than in the neat polymer with concomitant reductions in percolation threshold. [ABSTRACT FROM AUTHOR]

Multiwalled carbon nanotubes (MWCNTs) with aspect ratios (ARs) ranging from 94 to 474 were incorporated into polystyrene (PS)/poly(methyl methacrylate) blends using solution mixing and melt mixing. Also, two functionalized MWCNTs were prepared from the nanotubes having AR 94: one was oxidized by nitric acid while the other was further modified with amine-terminated PS attached to carboxyl groups to form amides. The two functionalized MWCNTs (1 wt %) were used to show that which phase the carbon nanotubes (CNTs) were located in could be controlled with nanotube surface chemistry. When nanotubes were confined to the minor phase, the size of the minor domain first decreased with adding low AR CNT as expected due to the increased viscosity of the minor phase. However, at higher ARs, the size increased beyond the size for the minor domain with no nanotubes, and at high enough AR, the shape of the minor domain changed from spherical to an elongated irregular shape. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3500-3510, 2015 [ABSTRACT FROM AUTHOR]

ABSTRACT Multiwalled carbon nanotubes (MWCNTs) were melt-mixed in a conical twin-screw extruder with a random copolymer of ethylene and tetrafluoroethylene. Surprisingly, the electrical percolation threshold of the resultant composites was quite low; ∼0.9 wt %. In fact, this value is as low or lower than the value for most MWCNT/semicrystalline polymer composites made with roughly equivalent aspect ratio tubes mixed in a similar manner, for example, melt mixing. This low percolation threshold, suggestive of good dispersion, occurred even though the polymer surface energy is quite low which should make tubes more difficult to disperse. Dynamic mechanical measurements confirmed the rather low percolation threshold. The effect of nanotubes on crystallization kinetics was quite small; suggesting perhaps that a lack of nucleation which in turn reduces/eliminates an insulating crystalline polymer layer around the nanotubes might explain the low percolation threshold. Finally, the modulus increased with the addition of nanotubes and the strain at break decreased. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41052. [ABSTRACT FROM AUTHOR]

ABSTRACT Two multi-walled carbon nanotubes (MWCNTs) having relatively high aspect ratios of 313 and 474 with approximately the same diameter were melt mixed with polycarbonate (PC) in a twin-screw conical micro compounder. The effects of aspect ratio on the electrical, mechanical, and thermal properties of the PC/MWCNT composites were investigated. Electrical conductivities and storage moduli of the filled samples are found to be independent of the starting aspect ratio for these high aspect ratio tubes; although the conductivities and storage moduli are still significantly higher than values of composites made with nanotubes having more commercially common aspect ratios of ∼100. Transmission electron microscopy results suggest that melt-mixing reduces these longer nanotubes to the same length, but still approximately two times longer than the length of commercially common aspect ratio tubes after melt-mixing. Molecular weight measurements show that during melt-mixing the longer nanotubes significantly degrade the molecular weight of the polymer as compared to very similar nanotubes with aspect ratio ∼100. Because of the molecular weight reduction glass transition temperatures predictably show a large decrease with increasing nanotube concentration. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 73-83 [ABSTRACT FROM AUTHOR]

The bulk and shear rheological properties of a symmetric three-arm star polystyrene were measured using a self-built pressurizable dilatometer and a commercial rheometer, respectively. The bulk properties investigated include the pressure-volume-temperature behavior, the pressure-dependent glass transition temperature ( Tg), and the viscoelastic bulk modulus and Poisson's ratio. Comparison with data for a linear polystyrene indicates that the star behaves similarly but with slightly higher Tgs at elevated pressures and slightly higher limiting bulk moduli in glass and rubbery states. The Poisson's ratio shows a minimum at short times similar to what is observed for the linear chain. The horizontal shift factors above Tg obtained from reducing the bulk and shear viscoelastic responses are found to have similar temperature dependence when plotted using T − Tg scaling; in addition, the shift factors also exhibit a similar temperature dependence to linear polystyrene. The retardation spectra for the bulk and shear responses are compared and show that the long time molecular mechanisms available to the shear response are unavailable to the bulk. At short times, the two spectra have similar slopes, but the short-time retardation spectrum for the shear response is significantly higher than that for the bulk, a finding that is, as yet, unexplained. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012 [ABSTRACT FROM AUTHOR]

Background: Chronic obstructive pulmonary disease (COPD) coexisting with lung cancer is associated with severe mortality and a worse prognosis. Inflammation plays an important role in common pathogenic pathways and disease progression. However, a few studies have identified the clinical value of the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) in COPD with lung cancer, which are systemic inflammatory response markers in the blood. This study aimed to determine the association of the NLR or PLR with clinical characteristics and whether NLR or PLR can be diagnostic markers for COPD with lung cancer., Methods: Between 2015 and 2021, we conducted a retrospective analysis of 236 COPD patients with lung cancer and 500 patients without lung cancer (control group). Clinical information, blood routine examination, and spirometry results were collected and analyzed. The receiver operating characteristic (ROC) curve was used to identify the best cutoff point of NLR or PLR. Multivariate logistic regression analysis was performed to evaluate the association of NLR or PLR with the diagnosis and prognosis of COPD with lung cancer., Results: Compared to patients in the COPD-only group, patients in the lung cancer group had a higher percentage of current smoking and emphysema, and it was found that NLR or PLR was significantly higher in the lung cancer group. Multivariate analysis showed that age, smoking status, FEV1%pred, emphysema, NLR, and PLR were independent risk factors for lung cancer development in COPD. Furthermore, the high level of NLR or PLR was associated with age over 70 years old, current smoking status, and ineligible surgery treatment. The level of PLR or NLR markedly increased with hypercoagulation status, the severity of airflow limitation, and advanced progression of lung cancer. Additionally, the ROC analysis also revealed that elevated NLR or PLR was an independent predictor of COPD in lung cancer patients, TNM stages IIIB-IV at first diagnosis in lung cancer, and ineligible surgery in lung cancer patients., Conclusion: Increased NLR or PLR values might be an important and easily measurable inflammation biomarker to predict the diagnosis and severity of lung cancer with COPD., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Ma, Wang, Du, Guo, Guo, Hu, Bai, Huang, Zhuang, Chen and Liu.)

Acute exacerbations show a significant impact on disease morbidity and mortality in chronic obstructive pulmonary disease (COPD). In contrast to stable COPD, the association of smoking status with clinical and laboratory characteristics in patients with acute exacerbations of COPD (AECOPD) has not been well studied. In this retrospective study, we compared never smokers and ever smokers on their demographic, clinical, and laboratory characteristics in a Chinese clinical cohort of AECOPD. In this cohort comprising 1,034 consecutive patients with AECOPD, never smokers were older (75 vs 70.5 years, p adjusted < 0.001) and had a higher body mass index than smokers (21.1 ± 4.0 vs 20.3 ± 3.4, p adjusted = 0.028). Furthermore, never smokers showed a decreased risk of recurrent acute exacerbation (13.0 vs 21.8%, p adjusted = 0.029), a lower risk of development of emphysema (77.8 vs 89.1%, p adjusted < 0.001), a lower prevalence of the co-morbidity of lung cancer (0.5 vs 6.6%, p adjusted < 0.001), lower levels of circulating eosinophils (EO; 0.04 × 10 9 /L vs 0.10 × 10 9 /L, p adjusted = 0.007) and basophils (BA; 0.02 × 10 9 /L vs 0.03 × 10 9 /L, p adjusted = 0.019), and a higher plasma levels of D-dimer (0.62 μg/ml vs 0.51 μg/ml, p adjusted = 0.02). Furthermore, multivariate logistic regression analysis identified several risk factor for the recurrent acute exacerbation, such as smoking [odds ratio ( OR ) = 1.84, 95% CI : 1.03-3.40, p = 0.044], urban residential area ( OR = 1.43, 95% CI : 1.01-2.05, p = 0.045), and the presence of emphysema ( OR = 2.31, 95% CI : 1.25-4.69, p = 0.012). In conclusion, this study demonstrates that the smoking status of patients is associated with recurrent acute exacerbations, emphysema, lung cancer, and levels of circulating EO and BA in AECOPD. Identification of cigarette smoking as a risk factor for recurrent acute exacerbation supports behavioral intervention of smoking cessation in the management of patients with AECOPD., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Wang, Ma, Zhang, Guo, Liu, Petersen, Wang and Yu.)