Rapid Decomposition of Epoxy Resins via Raman Spectrometry in Combination with Machine Learning Algorithms

Epoxy resins are a group of important materials that have been used everywhere,and development of new materials of this kind with optimal mechanical properties from either bio-resources or industrial precursors has drawn great focus from scientists and engineers.By reacting different kinds of epoxy adhesives and curatives,massive kinds of epoxy resins with different characteristics are produced.Determination of original mixing ratio of epoxy adhesives and corresponding curatives of their curing products is useful in controlling and examining these materials.Here in this work,we described an efficient method based on Raman spectrometry and machine learning algorithms for rapid molar composition determination of epoxy resins.Original mixing ratio of epoxy adhesives and curatives could be calculated simply via Raman spectra of the products.Raman spectral data scanned during curing procedure was fed to random forest(RF)classification to calculate weights of Raman shift features and reduce data dimensionality,then spectral data of selected features were processed by partial least squares regression(PLSR)for model training and composition ratio determination.It turned out that ratio predictions of our model fit well to their actual values,with a coefficient of determination(R2)of 0.9926,and a root mean squared error(RMSE)of 0.0305.

Characterization of functionalized multiwalled carbon nanotubes and application as an effective filter for heavy metal removal from aqueous solutions

Filtration efficiency of Ni(II) from aqueous solution using pristine and modified MWCNTs filters was investigated as a function of Ni(II) ion concentration, p H, and filter mass. MWCNTs were synthesized by CVD method and modified using two complementary treatments, purification(using a mixture of hydrochloric acid and hydrogen peroxide) and functionalization(using nitric acid). The effect and mechanism of each treatment on the structural integrity of pristine MWCNTs has been studied. Morphology of the pristine and modified filters was investigated by Raman Spectrometry(RS), Scanning Electron Microscopy(SEM), Energy Dispersive X-ray Spectroscopy(EDS),Fourier Transform Infrared(FTIR) spectrometry and Thermogravimetric analysis. It was found from Raman spectra that the ratio of the intensity of D-band to that of G-band decreased by purification process, and increased by functionalization process. The adsorption mechanism of Ni(II) onto the surface functional groups of modified MWCNTs was confirmed by FTIR spectrum. The filtration results showed that the removal efficiency of Ni(II) is strongly dependent on pH and could reach 85% at pH = 8. Also, modified MWCNT filters can be reused through many cycles of regeneration with high performance. Functionalized MWCNTs filters may be a promising adsorbent candidate for heavy metal removal from wastewater.

Handheld Raman Spectrometer for the Rapid Determination of Synthetic Cannabinoids

A handheld laser Raman spectrometer was developed to detect 11 synthetic cannabinoid standards.The spectrometer can be connected with a mobile phone by Bluetooth or a computer by a data cable.The Raman spectra of the synthetic cannabinoids AM‑694,JWH‑019,and nine others were accurately determined by software analysis of characteristic Raman peaks.This technique is highly efficient,accurate,and simple,and it is a valid procedure for rapid on‑site investigations of cannabinoids.

Characterization and Wettability of ZnO Film Prepared by Chemical Etching Method

ZnO thin films were prepared by a chemical etching method and their wettability was investigated. The structure and surface composition structure were characterized by means of scanning electron microscopy, X-ray photoelectronic spectrometry（XPS）, X-ray diffraction（XRD） and Raman spectrometry. These analyses reveal that the etched films were large-scale micro-nanohierarchical structures composed of a Zn core and a ZnO coating. Superhy- drophobic surfaces with water contact angles of over 150~ were obtained by n-octadecanethiol（ODT） modification. The XPS and Raman results indicate that ODT molecules were bound to the ZnO surface with the S head group by forming Zn--S bond.