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Constructing a hierarchical structure of nanomaterials on the surface of reinforcing fibers is the best strategy to obtain other desired functions while improving the mechanical properties of polymers. In this article, acid-treated multiwall carbon nanotubes (MWCNTs) were introduced to the surface of milled glass fiber (MGF) under the combined action of tetraethyl orthosilicate and 3-aminopropyltriethyloxysilane to prepare a hierarchical fiber (MWCNTs-GF). The surface morphology and microstructure of this hierarchical fiber were characterized by field-emission scanning electron microscope and transmission electron microscope, and a composite coating with MWCNTs as the main component was observed on each fiber surface. Fourier transform infrared and Raman spectroscopy revealed the presence of the specific interactions between MWCNTs and MGF. Polyamide 66 (PA66) composites with different content of MWCNTs-GF were fabricated by melt blending. The resulting composites exhibited improved mechanical properties relative to pure PA66, in which the tensile strength and notched impact strength of the composite filled with 3 wt% MWCNTs-GF increased by 23.3% and 69.0%, respectively. Subsequently, by analyzing fracture morphology and interfacial adhesion of the composites, the strengthening and toughening mechanisms of MWCNTs-GF were elaborated in detail. In addition, the results of thermogravimetric analysis and differential scanning calorimetry showed that MWCNTs-GF possessed strong heterogeneous nucleation ability, and its addition could refine the grain size of PA66 and significantly increase the crystallization temperature and thermal stability of the corresponding composites. Compared to PA66 composites reinforced with neat MGF, it was found that the unique surface structure of MWCNTs-GF was likely responsible for improved thermal properties of this hierarchical fiber-reinforced PA66 composites.

BackgroundSelf-rated health has been widely used as a useful screening tool to subjectively evaluate individuals' health status. Under the context of the rapid growth of aging, there was a dramatic rapid expansion in internal older migrants in China. Serious concerns on the issues of health status continue to attract quite a lot of attention over the past decades. Public health education is one of the most important health care services and methods to improve individuals' health status. However, most previous studies focus on the utilization of public health services such as visiting to doctors, physical examination, and hospitalization. There was limited evidence on the self-rated health and public health education of older migrants.ObjectivesThe study aimed to evaluate self-rated health and the associated determinants in older migrants, as well as to gain a deeper insight into the current status of public health education received by older migrants.MethodsWe derived the data from the National Migrants Population Health and Family Planning Dynamic Monitor Survey 2018, a cross-sectional study, for secondary analysis. Internal migrants aged 60 years old or over were included in the study. Self-rated health was the dependent variable, while sociodemographic characteristics were the independent variable. The univariate and multivariate analyses were performed by Stata 15.1.ResultsA total of 5,589 older migrants were included in the study. Eighty-two percentage of older migrants reported healthy self-rated health. There was a significant association between age, gender, minzu, education level, monthly income, public health education, and self-rated health (P < 0.5). However, the proportion of older migrants that received specific public health education was <50%. The most common approach to receiving public health education was through the leaflet, while <20% of older migrants received public health education through public consultation and one-to-one education.ConclusionsIt was necessary to promote the publicity of public health education in older migrants through easy access and diverse approaches in order to effectively spread health-related knowledge to older migrants to satisfy their health needs and maintain their health.