Application Of Chemometrics Combined With NIR Dtection And Analysis Of NR Polymers

Dandelion rubber is a good substitute for natural rubber(NR),but in the actual production,it is necessary to screen the rubber plants,which requires research on the rubber content of dandelion rubber.The near-infrared spectrum stands out because of its excellent performance in green,fast and non-destructive testing,and is widely used in food,medicine,petroleum and many other fields.This topic firstly uses the Soxhlet extraction method to extract the rubber from dandelion rubber,and optimizes the solvent in the extraction.Finally,acetone is selected as the impurity removal solvent,toluene is used as the extraction solvent,and the extraction result using FT-IR and NMR analysis confirmed the purity of the extracted material.The rubber content was then quantitatively analyzed using GPC to obtain a quantitative curve:y=18454x-8575(R2=0.9945)with a linear range of 1 mg/mL to 8 mg/mL.After that,the content of 54 samples of 6 varieties of dandelion rubber dry rubber samples was tested.Then,the near-infrared spectroscopy(NIR)combined with the partial least squares algorithm was used to analyze the gel content of 54 samples.The model was established by using 8 spectral preprocessing methods.The results show that the modeling algorithm of the discontinuous band spectrum SG-1st-PLS shows very good adaptability.The correction coefficient Rcal2 is 0.8573 and the verification coefficient Rval2 is 0.8462.The accuracy rate reached 83.3%.At the same time,the natural rubber latex samples were studied by near-infrared transmission spectroscopy.The PLS model was established by using six spectral pretreatment methods.The results show that the discontinuous spectral SG-2nd-PLS model algorithm shows excellent model adaptability.The correction determination coefficient Rcal2 is 0.9956,the verification determination coefficient Rval2 is 0.9945,and the prediction accuracy is 90%.Finally,we set out to develop a miniaturized portable LED near-infrared spectroscopy instrument,and designed a series of LED light source devices for this near-infrared device,and performed corresponding performance tests.The spectrum of the whole instrument ranges from 1100 to 2500 nm,which breaks through the limitation of NIR spectrometers on the short-wave near-infrared on the market.It has a wider application range.The MCD circuit is used to realize the measurement mode of the pulse signal of the spectrometer.