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The exploitation of efficient lubricants for ABS resins is widely recognized as beneficial for industrial production. Fatty diamides are typically applied as the lubricants for ABS resins; however, the connection between fatty chain structures and the lubricating properties is still vague. In this work, a range of ethylenediamine‐based amide lubricants (EDA‐Cn) with different fatty chain structures were successfully prepared and chemical structures were characterized in detail by the Fourier transform infrared spectrometer and proton nuclear magnetic resonance. The rheological test results suggested that the complex viscosity and relaxation time were positively associated with the fatty chain lengths of EDA‐Cn. The dynamic mechanical analysis results confirmed that EDA‐Cn exhibited excellent compatibility with ABS resins. The lubricating effect of EDA‐Cn decreased with increasing fatty chain lengths, which was manifested by a higher glass transition temperature, and lower elongation at break of ABS resins. In comparison to EDA‐C22, the complex viscosity (angular frequency = 0.1 rad/s) and glass transition temperature of EDA‐C10 have decreased by 24.9% and 3.9%, respectively. The molecular dynamics simulations revealed the intrinsic mechanism of lubricant‐substrate interaction. The EDA‐Cn containing short fatty chain lengths reduced the interaction energy with the matrix, thereby promoting the diffusive movement of the chain segments, and resulted in the increase in the mean square displacement and improved flow properties. These findings provided sufficient theoretical basis for the rational design and preparation of lubricants for ABS resins. [ABSTRACT FROM AUTHOR]

Oral lichen planus (OLP) is a common chronic inflammatory disease with unclear etiology, in which disorder of the cell-mediated local immune response plays an important role. MicroRNAs (miRNAs) have been found to play an important role in the occurrence and development of inflammatory responses and autoimmune diseases. In recent years, many studies have reported that miRNAs may be related to OLP. According to a literature review, high expression of miRNA-19a and low expression of miRNA-122, miRNA-199, miRNA-138, miRNA-635 and miRNA-578 may be related to the occurrence of OLP by regulating cytokines such as interleukin, interferon and tumor necrosis factor. The low expression of miRNA-125a and the high expression of miRNA-132, miRNA-146a and miRNA-155 may be related to the severity of OLP by influencing the differentiation of CD4+ T cells in the Th1/Th2 subgroup. High expression of miRNA-26a, miRNA-29a and miRNA-31 and low expression of miRNA-27b, miRNA-200a and miRNA-137 may be associated with malignant risk of OLP through functionally related genomes, transcription factors and miRNA coregulatory networks. Some deficiencies remain in current studies. For example, many studies using microarrays to screen differentially expressed miRNAs have not been further grouped according to the type of OLP or cancer risk.

AbstractThe particle size of polybutadiene (PB) particles can be effectively controlled through polymer agglomeration. However, up to now, the impact of the particle size and concentration of agglomerated PB on the mechanical properties and rheological behavior of ABS terpolymer remains unclear. Our research described here studied the effect of the particle size and content of agglomerated PB on the mechanical and rheological properties of ABS. It was found that the impact strength of ABS with a bimodal size distribution of PB (67/452 nm) exceeded that of ABS with a unimodal PB size distribution within the PB content range studied. Furthermore, the impact strength of the ABS containing 319 nm PB above the brittle-toughness transition point was greater than that of other ABS containing unimodal PB at the same PB content. For ABS with a unimodal PB distribution, the PB contents of ABS containing 220, 319, and 415 nm PB at the brittle ductile transition point were 14%, 12%, and 16%, respectively. The tensile strength and melting index of the ABS containing different particle sizes of agglomerated PB decreased linearly with the increase of PB content. Rheological tests showed the viscosity and dynamic viscoelastic properties of the ABS blends. All ABS exhibited shear-thinning behavior, and the addition of PB content resulted in more elastic than viscous behavior in the ABS blends. At the same angular frequency (ω), higher PB content corresponded to greater complex viscosity in the ABS blends. In addition, as the PB content in ABS was increased, it exhibited more solid-like behavior. This study, we suggest, provides a good insight into the effect of agglomerated PB on the ABS/PB blend properties and explores practical applications for the polymer agglomeration of polybutadiene latex (PBL). [ABSTRACT FROM AUTHOR]

As a high‐performance engineering plastic, the acrylonitrile‐butadiene‐styrene (ABS) resin possesses excellent heat resistance, chemical resistance, and toughness. However, there is a lack of flow properties of the ABS resin for many processing operations. With the aim of enhancing the flowability of the ABS resin, the effect of N,N′‐ethylene bis oleamide (EBO) as a new lubricant on the melt flow rate (MFR), torque value, and rheological behavior of the ABS resin was investigated. The result showed the MFR of the ABS resin with 2.0 wt% EBO was 22.1 g/10 min, which was improved by 49% compared with the pure ABS resin (14.8 g/10 min). The torque value of the ABS resin, including 2.0 wt% EBO (1.69 N m) was lower than that of the pure ABS resin (2.03 N m). The rheological study further indicated that EBO can reduce the complex viscosity of the ABS resin. The above results indicated that EBO was an effective lubricant for the ABS resin. A possible lubrication mechanism was proposed based on the consequences of the rotational rheometry, dynamic mechanical analysis, and molecular dynamics simulation. EBO decreased the entanglement density of the polystyrene‐acrylonitrile (SAN) molecular chains and increased the mobility of the SAN molecular chain segments. On the other hand, EBO increased the free space of motion of the SAN molecular chain segments due to the free‐volume effect thereby increasing the mean square displacement of the system. This work will provide a new way to achieve the high‐flow ABS resin and provide new insights into the lubrication mechanism of lubricants in the ABS resin thereby expanding the applications of the ABS resin. [ABSTRACT FROM AUTHOR]

Acrylonitrile-butadiene-styrene (ABS) resin is a typical elastomer-toughening plastic, where the rubber component is polybutadiene (PB). In this paper, the influence of PB-g-Styrene-Acrylonitrile (SAN) concentration on the mechanical properties as well as the flow behavior of the ABS resin was studied. The notched impact strength of the ABS resin including 30 wt% PB-g-SAN was 18.7 kJ/m2, more than five times as high as that of neat SAN resin (3.8 kJ/m2). Scanning electron microscopy (SEM) examination confirmed that the primary reason of the improved toughness of the ABS resin was the shear yielding effect of the matrix. Additionally, a melt flow indexer, rotating rheometer, torque rheometer and dynamic mechanical analyzer (DMA) were utilized to analyze the influence of PB-g-SAN concentration on the ABS resin flow behavior. The results showed that the melt flow rate (MFR) of the ABS resin decreased linearly and the complex viscosity (η*) as well as the tensile plateau modulus (E') values increased significantly with the growing concentration of PB-g-SAN. This indicated that the flow behavior of the ABS resin was negatively affected when excess PB-g-SAN concentration was added. The entanglement effect between the SAN copolymer on the PB particles surface and the matrix SAN molecular chains, as well as the PB particle volume effect, were suggested to be the main reasons of the negative effect. This research, we suggest, will provide profound scientific guidance for regulating the mechanical and processing characteristics of the ABS resin. [ABSTRACT FROM AUTHOR]