CN-122017054-A - Analysis method of copolymer sequence structure and application thereof

Abstract

The invention relates to the technical field of high polymer material detection, in particular to an analysis method of a copolymer sequence structure and application thereof. The method is characterized in that the copolymer powder is subjected to high-temperature pyrolysis under the action of a pyrolysis catalyst, and a pyrolysis product is subjected to gas chromatography mass spectrometry analysis, so that the sequence structure of the copolymer is obtained. The invention realizes the determination and good separation of various sequence structures in the copolymer by optimizing the separation conditions of the gas chromatography. The invention can realize the measurement and separation of twenty-six sequence structures after the pyrolysis of the polyoxymethylene and six sequence structures after the pyrolysis of the styrene-acrylonitrile copolymer, and the measured sequence structures are comprehensive in variety and high in separation degree, thereby effectively improving the accuracy of sequence distribution analysis.

Inventors

• XIE XIAOQIONG
• Xia Xiangjiao
• PANG CHENGHUAN
• WU BO
• CHEN PINGXU
• YE NANBIAO
• LI JIANJUN

Assignees

• 国高材高分子材料产业创新中心有限公司

Dates

Publication Date

20260512

Application Date

20250331

Claims (10)

1. 1. A method for analyzing the sequence structure of a copolymer, comprising the steps of: s1, uniformly mixing copolymer powder to be detected with a cracking catalyst to obtain a sample to be detected; s2, analyzing the sample to be detected by adopting a cracking-gas chromatography-mass spectrometry method to obtain a sequence structure of the copolymer; wherein the stationary phase of the gas chromatography is selected from nonpolar phenyl aryl polymers, and the temperature rise program is that the temperature rise rate is increased to 280-300 ℃ at 5 ℃ per minute, and the temperature is kept for 5-10min.
2. 2. The method of claim 1, wherein the cleavage catalyst is selected from an acidic catalyst or a basic catalyst.
3. 3. The method according to claim 2, wherein the cracking catalyst is at least one selected from the group consisting of cobalt sulfate heptahydrate, cobalt nitrate hexahydrate, zinc oxide, and ferric oxide. .
4. 4. The method according to claim 1, wherein the amount of the cracking catalyst 15 is 15wt% to 30wt% of the total mass of the cracking catalyst and the polyoxymethylene powder.
5. 5. The method of claim 1, wherein the cleavage temperature of the cleavage is 400-450 ℃.
6. 6. The method of claim 1, wherein the gas chromatography column is DB-5MS.
7. 7. The method of claim 1, wherein the split flow rate of the gas chromatograph is 1.0-1.2mL/min.
8. 8. The method of claim 1, wherein the purge flow rate of the gas chromatograph is 1.0-1.2mL/min.
9. 9. The method of claim 1, wherein the ion source temperature of the mass spectrum is 280 ℃.
10. 10. The method of claim 1, wherein the copolymer is polyoxymethylene or a styrene-acrylonitrile copolymer.

Description

Analysis method of copolymer sequence structure and application thereof Technical Field The invention relates to the technical field of high polymer material detection, in particular to an analysis method of a copolymer sequence structure and application thereof. Background Resins such as Polyoxymethylene (POM), styrene-acrylonitrile copolymer (SAN), acrylonitrile-butadiene-styrene copolymer (ABS) and styrene-butadiene-styrene copolymer (SBS) have excellent physicochemical properties, and are widely used in the fields of electronics, machinery, instruments, light industry, automobiles, building materials, agriculture, etc. Such resins are typically polymerized from two or more monomers together to form a copolymer containing two or more monomer units. Random copolymers, alternating copolymers, block copolymers and graft copolymers can be classified according to the manner in which the various monomers are arranged in the molecular chain of the copolymer. The distribution of the copolymerized unit structure in the copolymer has important influence on the density, crystallinity, thermal stability and other properties of the resin. Taking POM as an example, the POM resin has very high rigidity and hardness, very good fatigue resistance and wear resistance, small creep property and water absorption, good dimensional stability and chemical stability, and the like, and is engineering plastic with good comprehensive performance and wide application range. The POM main chain mainly comprises a methylene chain segment (-CH 2O-) and has a molecular weight of tens of thousands to hundreds of thousands, and the POM main chain has a regular and symmetrical molecular structure due to the fact that the POM main chain has no side chains, so that the POM main chain has higher density and crystallinity. However, when the molecular main chain of POM is composed of only pure (-CH 2O-) chain segments, the thermal stability is extremely poor, and rapid formaldehyde-free chain reaction tends to occur under the action of light, heat, oxygen and strong acid, so that the whole polymer chain is completely depolymerized, and the product performance is extremely reduced. Therefore, in general, the thermal stability of POM is improved by introducing an ethylene oxide segment (-CH 2CH 2O-) into its molecular main chain during its polymerization. Therefore, in polyacetal copolymers, the analysis of the sequence structure and the distribution thereof are studied, and the estimation of the content and distribution of-CH 2CH 2O-units is extremely important for the study of various properties of polyacetal copolymers. Currently, the research methods for the sequence structure of the copolymer mainly include a nuclear magnetic method, a hydrolysis method, a chemical decomposition method, a thermal decomposition method and the like. Patent CN114486974a discloses an analysis method of sequence structure distribution of random ethylene-propylene copolymer, firstly using deuterated o-dichlorobenzene solvent to fully dissolve random ethylene-propylene copolymer to be tested, then adding the obtained solution into a nuclear magnetic tube, and selecting conventional 13C NMR spectrum measurement mode to obtain quantitative carbon spectrum of random ethylene-propylene copolymer. And secondly, dividing integral peak areas by utilizing a quantitative carbon spectrum of the random ethylene-propylene copolymer, correlating types of carbon-containing functional groups corresponding to different integral peaks, and determining the type of carbon corresponding to the integral peak. And finally, deducing a calculation formula of sequence structure distribution according to the relation between each integral peak and the attributive functional group, and calculating the unitary and ternary sequence structure distribution of the random ethylene-propylene copolymer to be detected by using the calculation formula. In patent CN111978449a, a method for studying the sequence structure of an acrylate-ethylene copolymer is disclosed, which uses deuterated chloroform to dissolve the copolymer, characterizes its copolymer unit composition by nuclear magnetic resonance spectroscopy, and calculates the compositions of methyl acrylate units and 1-octene units, respectively. In addition, the copolymer structure is analyzed to be a methyl acrylate-methyl acrylate full-alternating structure by utilizing the nuclear magnetic carbon spectrum to characterize the copolymer unit sequence structure. The nuclear magnetic method for analyzing the copolymer sequence structure is simple in operation and high in accuracy, but expensive nuclear magnetic equipment is needed, and the copolymer units and the sequence structures of different copolymers are large in difference, so that the method is not completely suitable for analyzing all copolymer sequence structures, is high in test cost, and can only analyze the single-element to ternary sequence structure distribution of the copolymer, a