CN107167552A - A kind of method for determining sulfur content in rubber and rubber product - Google Patents
A kind of method for determining sulfur content in rubber and rubber product Download PDFInfo
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- CN107167552A CN107167552A CN201610798183.5A CN201610798183A CN107167552A CN 107167552 A CN107167552 A CN 107167552A CN 201610798183 A CN201610798183 A CN 201610798183A CN 107167552 A CN107167552 A CN 107167552A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
- G01N31/16—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using titration
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/44—Sample treatment involving radiation, e.g. heat
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Abstract
The present invention provides a kind of method for determining total sulphur content in rubber and rubber product, including：Handle sample；Micro-wave digestion；Catch up with acid；Titrated with potentiometric titrimeter；Calculation results.Compared with GB/T 4497.1 2010, the method that provides of the present invention is quick, easily sentence terminal, the reproducible, degree of accuracy is high, and measurement range is wide, it is adaptable to determine the total sulphur content in the rubber and rubber product except barium sulfate-containing.
Description
Technical field
The present invention relates to a kind of method of testing of total sulphur content in rubber and rubber product, more specifically, it is related to one kind
The method that total sulphur content in rubber and rubber product is determined using micro-wave digestion-constant-current titration.
Background technology
With the development of science and technology, rubber is widely used in the row such as building, communications and transportation, machine-building, weaving, national defence
Industry.Vulcanization is one of most important link in rubber production process, and rubber macromolecular is only through over cure, and crosslinking forms tool
There is the build macromolecular of tridimensional network, can just obtain excellent high resiliency, high intensity, as the material for thering is actual use to be worth
Material.The rubber physical performance of different crosslinking degrees has very big difference, therefore finds total sulphur content in a kind of quick detection rubber
Method it is most important.
At present determine sulfur content method have Oxygen bottle combustion-titration, the sodium peroxide-precipitation method, high temperature furnace burning-
Infrared method, the Oxygen Bomb Combustion-chromatography of ions, AAS, atomic absorption spectrography (AAS), emission spectrometry, X-ray fluorescence spectra
Method, inductively coupled plasma mass spectrometry etc..There are many kinds although determining the method for sulphur, mostly there is respective limitation, example
As Oxygen bottle combustion-titration is time-consuming, measurement range is narrow；AAS is time-consuming, processing sample is complicated, be adapted to determine low content
Sample；Atomic absorption method sensitivity is low, and disturbing factor is more, is adapted to the sample for determining high content；X-ray fluorescence spectra and inductance coupling
Conjunction plasma mass, expensive equipment,16O16O+,14N18O+,15N17O+,14N17OlH+It can form dry etc. a variety of multi-atomic ions
Disturb.
The assay method generally used in rubber and rubber industry at present is that GB/T 4497.1-2010 rubber is complete
The measure part 1 of sulfur content：Oxygen flask combustion method.The method has the following disadvantages：
1) detection range is narrow：The finite volume of oxygen bottle, directly determines that the measurement range of this method is narrow.
2) minute is long：According to national standard method, 1 sample can only once be tested by often covering burner.
3) poor repeatability：It cannot be guaranteed that the degree of each sample combustion is the same.
4) it is difficult to control：Easily there is the situation of incomplete combustion, sulphur changes into sulfate radical this step and is not easily controlled.
5) endpoint is difficult：This titration is precipitation titration, and end point mutation is not obvious, and human factor is larger.
Accordingly, it would be desirable to it is a kind of more rapidly, more succinct, more accurate, safer, the detection side that detection range is wide, reproducible
Method.
The content of the invention
The technical problems to be solved by the invention are to provide full sulphur in a kind of quick effectively measure rubber and rubber product and contained
The method of amount.
To achieve these goals, inventor have developed one kind and use micro-wave digestion, utilize potentiometric titrimeter to determine rubber
The method of total sulphur content in glue and rubber product, this method is complete the rubber and rubber product except barium sulfate-containing suitable for determining
Sulfur content.
According to the present invention, determining the method for total sulphur content in rubber and rubber product includes：Handle sample；Micro-wave digestion；
Catch up with acid；Titrated with potentiometric titrimeter；Calculation results.
Specifically, comprised the following steps according to the method for total sulphur content in the measure rubber and rubber product of the present invention：
Step 1, by sample grinds；
Step 2, a certain amount of sample is accurately weighed, is placed in micro-wave diminishing pot, a certain amount of concentrated nitric acid progress is added micro-
Ripple is cleared up, and completion to be cleared up is transferred the solution into beaker；
Step 3, acid is caught up with heating, the solution evaporation in beaker is done near；
Step 4, add after a certain amount of water and organic solvent, on potentiometric titrimeter, use plumbi nitras standard titration solution
Titration, obtains titration curve and titration results；
Step 5, Calculation results
The weight/mass percentage composition WX of full sulphur is calculated by Formulas I：
In formula：
The volume of plumbi nitras standard titration solution, mL needed for V- is titrated to flex point；
The concentration of c- plumbi nitras standard titration solutions, mol/L；
The molal weight of M- element sulphurs, g/mol；
The quality of m- samples, mg.
Wherein, by sample grinds in step 1, the device used is freeze grinding instrument.
Micro-wave digestion condition in step 2 is：Power supply 220V ± 10%, 15-30 DEG C of environment temperature, relative humidity 20%-
80%, power 400-1600W.The temperature and time of micro-wave digestion directly affects whether carbon black is resolved completely, and this method disappears
Temperature control is solved at 150-220 DEG C, preferably 180-200 DEG C, digestion condition is warming up to and keeps 20-40min at this temperature, it is excellent
Select 25-35min；Concentrated nitric acid consumption is excessive, and in order to reach higher pressure, concentrated nitric acid consumption is not less than 5mL.
In step 3, beaker is put into heating on electric hot plate and catches up with acid.
In step 4, one kind or several in the one or more that organic solvent can be in alcohols, preferably C2-C5 alcohol
Plant, most preferably the one or more in methanol, ethanol, isopropanol；The cumulative volume of water and organic solvent is 50-150mL, preferably
80-120mL；The volume ratio of water and organic solvent is 1:1-1:10, preferably 1:2-1:7, control the volume ratio of water and organic solvent
Extremely important to titration results, if beyond the scope, potential break response is smaller, and if disturbing factor, just having can
It can not judge which hop is terminal；Potentiometric titrimeter is using lead electrode as measuring electrode, and biliquid saturated calomel electrode is reference
Electrode；The molar concentration of plumbi nitras standard titration solution is 0.01mol/L-0.05mol/L, preferably 0.01mol/L-0.03mol/
L。
Compared with GB/T 4497.1-2010, the method for testing that the present invention is provided has the advantages that：
(1) this method easily clears up sample grinds completely；The micro-wave digestion of HTHP, clears up more abundant.
(2) this method uses the wider sample size of micro-wave diminishing pot energy process range.
(3) this method uses potentiometric titrimeter, and end point mutation substantially, can obtain preferable repeated and higher accurate
Property；Potentiometric titrimeter is indicator electrode from lead electrode, more direct than common platinum electrode, will not be by other anion factors
Interference.
(4) operating procedure of this method is few, and micro-wave digestion can handle multiple samples simultaneously, and minute is than national standard side
Method is greatly shortened.
Embodiment
The present invention is further described with reference to embodiment.The scope of the present invention is not restricted by the embodiments, this hair
Bright scope is proposed in detail in the claims.
Experimental facilities model and manufacturer used in the embodiment of the present invention see the table below shown in 1.
The experimental facilities model of table 1 and manufacturer
| Experimental facilities model and title | Manufacturer |
| MM400 freeze grinding instrument | German Lay is speeded Retsch GmbH |
| MARS micro-wave digestions/extraction all-in-one machine | U.S. CE M |
| ZDJ-3D autopotentiometric titrators | Beijing pioneer's prestige cutting edge of a knife or a sword technology development co. |
The preparation of cured rubber samples
Vulcanize rubber compounding (mass fraction)：
Component one：
Component two：
Vulcanize rubber preparation technology：In 1.6 liters of Banbury banburies (production of FARREL companies), component one is added, by
Gradually it is warming up to 160 DEG C and mixes 6 minutes, obtains elastomeric compound, parked 20 hours in room temperature；Then in banbury, 145 DEG C will be mixed
Refining glue and component two are mixed 5 minutes；Using XK-160 opening rubber mixing machines, (Qingdao Xin Chengyiming rubber manufacturing machineries Co., Ltd gives birth to
Production) it is stand-by to said mixture progress slice；Then in BH-25T vulcanizing presses (Jiangdu area Zhen Wu towns Bo Hai test machines factory
Production) on be molded (160 DEG C of curing temperature, cure time 30min), be made cured rubber samples.
Embodiment 1：Total sulphur content in vulcanization rubber is determined according to the inventive method
Step 1, sample is worn into 0.5mm or so powder with freeze grinding instrument.
Step 2,60mg or so sample is accurately weighed, is placed in micro-wave diminishing pot, 8mL is added and analyzes pure concentrated nitric acid, group
It is put into after dress counteracting tank in micro-wave digestion rotating disk and starts to clear up.Power supply 220V ± 10%, 25 DEG C of environment temperature, relative humidity
60%, set micro-wave digestion condition as：Power 800W, 180 DEG C of digestion condition, 45min is warming up to digestion condition and in this temperature
Lower holding 30min, waits that clearing up completion transfers the solution into 100mL beaker；
Step 3, beaker is put into heating on electric hot plate and catches up with acid, the solution evaporation in beaker is done near；
Step 4,20mL distilled water is added, 60mL ethanol is added, using lead electrode as measuring electrode, biliquid saturation is sweet
Mercury electrode is reference electrode, on potentiometric titrimeter, is titrated, is dripped with about 0.01mol/L plumbi nitras standard titration solution
Determine curve and titration results；
Step 5, Calculation results
The weight/mass percentage composition W of full sulphurXCalculated by Formulas I：
In formula：
The volume of plumbi nitras standard titration solution, mL needed for V- is titrated to flex point；
The concentration of c- plumbi nitras standard titration solutions, mol/L；
The molal weight of M- element sulphurs, g/mol；
The quality of m- samples, mg.
Test result is shown in Table 2.
Comparative example 1：The total sulphur content in vulcanization rubber is determined according to GB/T 4497.1-2010
Step 1,5mL 2% (mass fraction) hydrogen peroxide absorbing liquid is added in 1L oxygen Molotov cocktail.
Step 2,60mg or so sample is weighed, sample is wrapped up with ashless filter paper and is folded so that sample is wrapped completely.
Step 3, a tubule is inserted to the bottom of oxygen Molotov cocktail flask from storage oxygen steel cylinder, oxygen is led to 500mL/min flow velocity
5min.Oxygen hose is quickly drawn out, lights and rapidly inserts combustion head in oxygen Molotov cocktail after filter paper, combustion head is screwed and adds distilled water
Form water seal.2h is placed, allows absorbing liquid to fully absorb the gas of burning generation.
Step 4, the absorbing liquid in oxygen Molotov cocktail is poured into 100mL beaker, with 5mL distillation washing oxygen Molotov cocktails
Wall and combustion head, and cleaning solution is collected in same beaker, repeat and wash twice.Heating is boiled, and allows excessive hydrogen peroxide
Decompose, allow solution to be evaporated to 10mL.
Step 5,50mL isopropanols are added in beaker makes the volume fraction of alcohol in solution be between 70%~90%, plus
The thoron of 2~3 drops 0.5%, from 5mL microburets, is titrated to surely with about 0.01mol/L barium perchlorate standard liquid
Fixed pink is terminal.
Step 6, Calculation results
The weight/mass percentage composition W of full sulphurXCalculated by Formulas I：
In formula：
V- samples consume the volume of barium perchlorate standard titration solution, mL；
The concentration of c- barium perchlorate standard titration solutions, mol/L；
The molal weight of M- element sulphurs, g/mol；
The quality of m- samples, mg.
Test result is shown in Table 2.
The test result of the embodiment 1 of table 2. and comparative example 1
It can be seen that from the test result of table 2：This method can obtain preferably repeated and higher standard than national standard method
True property, and operating procedure is few, minute is greatly shortened than national standard method.
Embodiment 2：Total sulphur content in vulcanization rubber is determined according to the inventive method
Step 1, sample is worn into 0.5mm or so powder with freeze grinding instrument.
Step 2,100mg or so sample is accurately weighed, is placed in micro-wave diminishing pot, 10mL is added and analyzes pure concentrated nitric acid,
It is put into after assembling counteracting tank in micro-wave digestion rotating disk and starts to clear up.Power supply 220V ± 10%, 28 DEG C of environment temperature, relative humidity
65%, set micro-wave digestion condition as：Power 800W, 200 DEG C of digestion condition, 45min is warming up to digestion condition and in this temperature
Lower holding 35min, waits that clearing up completion transfers the solution into 100mL beaker；
Step 3, beaker is put into heating on electric hot plate and catches up with acid, the solution evaporation in beaker is done near；
Step 4,10mL distilled water is added, 70mL isopropanol is added, using lead electrode as measuring electrode, biliquid saturation
Calomel electrode is reference electrode, on potentiometric titrimeter, is titrated, obtained with about 0.02mol/L plumbi nitras standard titration solution
Titration curve and titration results；
Step 5, Calculation results
The weight/mass percentage composition W of full sulphurXCalculated by Formulas I：
In formula：
The volume of plumbi nitras standard titration solution, mL needed for V- is titrated to flex point；
The concentration of c- plumbi nitras standard titration solutions, mol/L；
The molal weight of M- element sulphurs, g/mol；
The quality of m- samples, mg.
Test result is shown in Table 3.
The test result of the embodiment 2 of table 3.
The sample size scope of national standard is 40mg-80mg, if the 100mg of embodiment 2 or so sample is determined, because once
It can not burn completely, it is necessary to which the sample for the 50mg or so twice of burning, will cause minute to greatly increase, and operating procedure increases
Plus, deviation can increase again.Embodiment 2 illustrates that method of the invention being capable of the wider sample size of process range.
The above embodiment of the present invention is intended to clearly illustrate example of the present invention by taking natural rubber as an example, only,
And it is not the restriction to embodiments of the present invention.To those skilled in the art, on the basis of the above description also
Other various forms of changes or variation can be made, other various types of rubbers are tested, there is no need and unable to right
All embodiments are exhaustive.
Claims (10)
1. a kind of method for determining total sulphur content in rubber and rubber product, it is characterised in that comprise the following steps：
Step 1, sample is handled；
Step 2, micro-wave digestion；
Step 3, acid is caught up with；
Step 4, titrated with potentiometric titrimeter；
Step 5, Calculation results.
2. the method as described in claim 1, it is characterised in that specifically include following steps：
Step 1, by sample grinds；
Step 2, a certain amount of sample is accurately weighed, is placed in micro-wave diminishing pot, excessive concentrated nitric acid is added and carries out micro-wave digestion,
Completion to be cleared up is transferred the solution into beaker；
Step 3, acid is caught up with heating, the solution evaporation in beaker is done near；
Step 4, add after a certain amount of water and organic solvent, on potentiometric titrimeter, titrated with plumbi nitras standard titration solution,
Obtain titration curve and titration results；
Step 5, Calculation results
The weight/mass percentage composition W of full sulphurXCalculated by Formulas I：
In formula：
The volume of plumbi nitras standard titration solution, mL needed for V- is titrated to flex point；
The concentration of c- plumbi nitras standard titration solutions, mol/L；
The molal weight of M- element sulphurs, g/mol；
The quality of m- samples, mg.
3. method as claimed in claim 2, it is characterised in that by sample grinds in step 1, the device used grinds for freezing
Grind instrument.
4. method as claimed in claim 1 or 2, it is characterised in that the microwave digestion temperature in step 2 is 150-220 DEG C, excellent
Select 180-200 DEG C.
5. method as claimed in claim 4, it is characterised in that be warming up in step 2 after the digestion condition, keeps 20-
40min, preferably 25-35min.
6. method as claimed in claim 2, it is characterised in that concentrated nitric acid excess described in step 2 and consumption is not less than 5mL.
7. method as claimed in claim 2, it is characterised in that in step 4, one kind in alcohols of the organic solvent or
It is several, the one or more in the one or more preferably in C2-C5 alcohol, most preferably methanol, ethanol, isopropanol.
8. method as claimed in claim 2, it is characterised in that in step 4, the cumulative volume of the water and organic solvent is 50-
150mL, preferably 80-120mL；The volume ratio of the water and organic solvent is 1: 1-1: 10, preferably 1: 2-1: 7.
9. method as claimed in claim 1 or 2, it is characterised in that in step 4, the potentiometric titrimeter is using lead electrode as survey
Electrode is measured, biliquid saturated calomel electrode is reference electrode.
10. method as claimed in claim 2, it is characterised in that in step 4, mole of the plumbi nitras standard titration solution
Concentration is 0.01mol/L-0.05mol/L, preferably 0.01mol/L-0.03mol/L.
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Cited By (1)
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| CN112611831A (en) * | 2020-07-31 | 2021-04-06 | 健研检测集团有限公司 | Method for testing sulfur content in welding flux |
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Application publication date: 20170915 |