A study of sulfur bridges in filled natural rubber vulcanizates by pyrolysis gas chromatography with flame-photometric detection

1982 ◽  
Vol 27 (7) ◽  
pp. 2527-2537 ◽  
Author(s):  
Eva M. Andersson ◽  
Inger Ericsson ◽  
Lena Trojer
2021 ◽  
Author(s):  
Ying Chen ◽  
Dong Yiyang ◽  
Xiang Ma ◽  
Jiaru Li ◽  
Minmin Guo ◽  
...  

Abstract Background: Taraxacum kok-saghyz (TKS), a plant native to the Tianshan valley on the border between China and Kazakhstan and inherently rich in natural rubber, inulin and other bioactive ingredients, is an important industrial crop. TKS rubber is a good substitute for natural rubber. TKS's breeding work necessitates the need to screen high-yielding varieties, hence rapid determination of rubber content is essential for the screening. Conventional analytical methods cannot meet actual needs in terms of real-time testing and economic cost. Near-infrared spectroscopy analysis technology, which has developed rapidly in the field of industrial process analysis in recent years, is a green detection technology with obvious merits of fast measurement speed, low cost and no sample loss. This research aims to develop a portable non-destructive near-infrared spectroscopic detection scheme to evaluate the content of natural rubber in TKS fresh roots. Pyrolysis gas chromatography (PyGC), was chosen as the reference method for the development of NIR prediction model. Results: 208 TKS fresh root samples were collected from the Inner Mongolia Autonomous Region of China. Near-infrared spectra were acquired for all samples. Randomly two-thirds of them were selected as the calibration set, the remaining one-third as the verification set, and the partial least squares method was successfully used to establish a good NIR prediction model at 1080-1800nm with a performance to deviation ratio (RPD) of 5.54 and coefficient of determination (R2) of 0.95. Conclusions: This study showed that portable near-infrared spectroscopy could be used with ease for large-scale screening of TKS plants in farmland, and could greatly facilitate TKS germplasm preservation, high-yield cultivation, environment-friendly, high-efficiency and low-cost rubber extraction, and comprehensive advancement of the dandelion rubber industry thereof.


1972 ◽  
Vol 45 (5) ◽  
pp. 1295-1302 ◽  
Author(s):  
Marjorie J. Hackathorn ◽  
M. J. Brock

Abstract Pyrolysis-gas chromatography has indicated the presence of head-head structures in free radical initiated poly(isoprene)s. Microozonolysis has confirmed the presence of both head-head (15-20 per cent) and tail-tail (4-7 per cent) structures in these polymers. These structures (which are absent in natural rubber) are present in lesser amounts in Lithium and Ziegler poly(isoprene)s (1-3 per cent). Non-equivalent amounts of head-head and tail-tail structures in particular samples indicate a chain reversal in which neither head nor tail units are involved. It has been postulated that chain reversal may occur at points of 3,4 addition.


1968 ◽  
Vol 41 (2) ◽  
pp. 411-417 ◽  
Author(s):  
M. Jernejčič ◽  
L. Premru

Abstract Pyrolysis gas Chromatographic isothermal and temperature programed separation of volatile components of unvulcanized natural rubber and synthetic polyisoprene was made on P-E columns Q and U. Besides identifications, relative quantitative differences between pyrolysis degradations of natural rubber and synthetic polyisoprene in pyrolysis temperature range 550°–750° C were established. It was found that the method was not suitable for an analogous study of vulcanized samples.


2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Markus Heryanto Langsa

<p>Penelitian ini bertujuan untuk menentukan senyawa organik khususnya organic karbon terlarut (DOC) dari dua spesies daun tumbuhan (<em>wandoo eucalyptus </em>and <em>pinus radiate, conifer</em>) yang larut dalam air selama periode 5 bulan leaching eksperimen. Kecepatan melarutnya senyawa organic ditentukan secara kuantitatif dan kualitatif menggunakan kombinasi dari beberapa teknik diantaranya Total Organic Carbon (TOC) analyser, Ultraviolet-Visible (UV-VIS) spektrokopi dan pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS).</p><p>Hasil analisis DOC dan UV menunjukkan peningkatan yang tajam dari kelarutan senyawa organic di awal periode pengamatan yang selanjutnya berkurang seiring dengan waktu secara eksponensial. Jumlah relatif senyawa organic yang terlarut tergantung pada luas permukaan, aktifitas mikrobiologi dan jenis sampel tumbuhan (segar atau kering) yang digunakan. Fluktuasi profil DOC dan UV<sub>254</sub> disebabkan oleh aktifitas mikrobiologi. Diperoleh bahwa daun kering lebih mudah terdegradasi menghasilkan senyawa organic dalam air dibandingkan dengan daun segar. Hasil pyrolysis secara umum menunjukkan bahwa senyawa hidrokarbon aromatic dan fenol (dan turunannya) lebih banyak ditemukan pada residue sampel setelah proses leaching kemungkinan karena adanya senyawa lignin atau aktifitas humifikasi mikrobiologi membuktikan bahwa senyawa-senyawa tersebut merupakan komponen penting dalam proses karakterisasi DOC.</p>


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