Measurement of cross link densities of prevulcanized natural rubber latex and latex products using low-cost near infrared spectrometer

2021 ◽  
Vol 159 ◽  
pp. 113016
Author(s):  
Chin Hock Lim ◽  
Panmanas Sirisomboon
2017 ◽  
Vol 25 (6) ◽  
pp. 407-415 ◽  
Author(s):  
Chin Hock Lim ◽  
Panmanas Sirisomboon

The analysis of the cross-link density of prevulcanised natural rubber latex using near infrared spectroscopy was conducted using a Fourier transform near infrared spectrometer in diffuse reflection mode over the wavenumber range of 12500–3600 cm−1. As the density of cross-link is an indication of the degree of cure, hence the properties of the latex products, the proposed method is useful for industrial purposes. For samples of prevulcanised latex of 50% total solids content (i.e. PV 50%) at 100% extension (prevulcanisate relaxed modulus 100%), the best model was developed using the partial least squares regression from the spectra, which were pre-treated using the first derivative method, where the coefficient of determination (r2), root mean square error of prediction and bias were 0.66, 6.06 × 104 Nm−2 and 1.63 × 104 Nm−2, respectively. The ratio of standard error of prediction to the standard deviation of the reference data in the prediction sample set was 1.8. This model could be used for screening. For samples at 300% extension (prevulcanisate relaxed modulus 300%) for PV 50%, the best model was developed using spectra pre-treated for scattering correction: r2, root mean square error of prediction and bias were 0.88, 6.74 × 104 Nm−2 and 1.35 × 104 Nm−2, respectively and the ratio of prediction to deviation was 3.0. Hence, the near infrared spectroscopy technique can be utilised as a rapid screening method for estimating the cross-link densities of prevulcanised natural rubber latex.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Heitor Dias Murbach ◽  
Guilherme Jaques Ogawa ◽  
Felipe Azevedo Borges ◽  
Matheus Carlos Romeiro Miranda ◽  
Rute Lopes ◽  
...  

Natural rubber latex (NRL) fromHevea brasiliensisis easily manipulated, low cost, is of can stimulate natural angiogenesis and cellular adhesion, is a biocompatible, material and presents high mechanical resistance. Ciprofloxacin (CIP) is a synthetic antibiotic (fluoroquinolone) used in the treatment of infection at external fixation screws sites and remote infections, and this use is increasingly frequent in medical practice. The aim of this study was to develop a novel sustained delivery system for CIP based on NRL membranes and to study its delivery system behavior. CIP was found to be adsorbed on the NRL membrane, according to results of energy dispersive X-ray spectroscopy. Results show that the membrane can release CIP for up to 59.08% in 312 hours and the mechanism is due to super case II (non-Fickian). The kinetics of the drug release could be fitted with double exponential function X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy shows some interaction by hydrogen bound, which influences its mechanical behavior.


2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Natan Roberto de Barros ◽  
Paulo Augusto Marques Chagas ◽  
Felipe Azevedo Borges ◽  
Jose Lucio Padua Gemeinder ◽  
Matheus Carlos Romeiro Miranda ◽  
...  

The aim of this study was to design a compound transdermal patch containing diclofenac potassium (Dic-K) using natural rubber latex (NRL) biomembrane. The NRL from Hevea brasiliensis is easily manipulated and low cost and presents high mechanical resistance. It is a biocompatible material which can stimulate natural angiogenesis and is capable of adhering cells on its surface. Recent researches have used the NRL for Transdermal Drug Delivery Systems (TDDSs). Dic-K is used for the treatment of rheumatoid arthritis and osteoarthritis and pain relief for postoperative and posttraumatic cases, as well as inflammation and edema. Results showed that the biomembrane can release Dic-K for up to 216 hours. The kinetics of the Dic-K release could be fitted with double exponential function. X-ray diffraction and Fourier Transform Infrared (FTIR) spectroscopy show some interaction by hydrogen bound. The results indicated the potential of the compound patch.


Author(s):  
KMZ Hossain ◽  
AM Sarwaruddin Chowdhury

Natural rubber latex (NRL) and n-butyl acrylate (n-BA) were blended and irradiated at various absorbed doses by gamma rays from Co-60 source at room temperature. The stabilizing effect was determined by measuring the pH and viscosity of NRL with n-BA with the storage time of five weeks. The cross-link density, swelling ratio of the radiation vulcanized rubber film were measured. The cross-link density of the n-BA grafted NRL film was found increasing and the swelling ratio of that film decreasing with the increased absorbed dose. The optimum radiation dose for better cross-linking of natural rubber latex blended with five parts per hundred rubber (phr) n-BA was found 15 kGy absorbed dose. Based on the cross-linking properties a probable cross-linking reaction mechanism for the n-BA grafted natural rubber latex film was developed. Keywords: Natural rubber latex, n-butyl acrylate, Irradiation, Swelling ratio, Cross-link, Reaction mechanism. DOI: 10.3329/diujst.v5i1.4386 Daffodil International University Journal of Science and Technology Vol.5(1) 2010 pp.81-88


2020 ◽  
Vol 10 (23) ◽  
pp. 8707
Author(s):  
Svetlana Pakhomova ◽  
Igor Zhdanov ◽  
Bert van Bavel

Plastic pollution in the marine environment has turned into an important research topic in recent decades. Until recently, studies were often based on visual assessment only, which is not enough to draw any conclusion about the chemical nature of found plastic items and could lead to incorrect results. Standardized, fast, and efficient low-cost methods for marine plastic litter identification are urgently needed to monitor the occurrence and distribution worldwide. In this paper, we demonstrate that a miniaturized handheld near-infrared spectrometer—MicroNIR—can be used for on-site identification of different plastic polymers. A database containing polymer spectra of the most produced and reported polymer types in the marine environment was created including polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polystyrene (PS), polyvinyl chloride (PVC), polyamide (PA), polycarbonate (PC), polyurethane (PUR), and Silicone. Using spectral match value (SMV, included in the instrument software) for spectra analysis resulted in an accurate classification of all nine polymer types. The method was used for the identification of marine macro-, meso-, and microplastic litter collected on beaches in sediments and seawater and enabled the correct identification of marine plastic litter for macro-, meso- (96%), and microplastics (73%) with exception of totally black items and items less than 1 mm in size. The method and instrumentation presented here are very well suited to support “Citizen Science” marine litter monitoring projects during beach cleaning and similar activities.


2003 ◽  
Vol 11 (2) ◽  
pp. 83-95
Author(s):  
Nathalie Szydlowski-Zanier ◽  
Marc Berger ◽  
François Wahl ◽  
Denis Guillaume

The performance of a Fourier-transform near infrared (FT-NIR) spectrometer equipped with an autosampling accessory (AutoSamplIR) using disposable vials with uncontrolled pathlength has been compared with the performance of an FT-NIR equipped with a manual vial sampling accessory using a reusable cell with calibrated pathlength. The effect of different parameters such as the signal-to-noise ratio, the stability of the purge and the linearity of absorbance have been evaluated by means of the NIR predictions of two physico-chemical properties of interest for gasoils, i.e the wt% of hydrogen and the cetane number (CN). It has been shown that an FT-NIR with the autosampling accessory can be used advantageously at low cost for quick and precise analyses of small amounts of sample.


Micromachines ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 478 ◽  
Author(s):  
Jian Huang ◽  
Quan Wen ◽  
Qiuyu Nie ◽  
Fei Chang ◽  
Ying Zhou ◽  
...  

This paper presents a dispersive near-infrared spectrometer with features of miniaturization, portability and low cost. The application of a resonantly-driven scanning grating mirror (SGM) as a dispersive element in a crossed Czerny–Turner configuration enables the design of a miniaturized spectrometer that can detect the full spectra using only one single InGaAs diode. In addition, a high accuracy recalculation is realized, which can convert time-dependent measurements to spectrum information by utilizing the deflection position detector integrated on SGM and its associated closed-loop control circuit. Finally, the spectrometer prototype is subjected to a series of tests to characterize the instrument’s performance fully. The results of the experiment show that the spectrometer works in a spectral range of 800 nm–1800 nm with a resolution of less than 10 nm, a size of 9 × 7 × 7 cm3, a wavelength stability better than ±1 nm and a measuring time of less than 1 ms. Furthermore, the power consumption of the instrument is 3 W at 5 V DC, and the signal-to-noise ratio is 3267 at full scale. Therefore, this spectrometer could be a potential alternative to classical spectrometers in process control applications or could be used as a portable or airborne spectroscopic sensor.


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