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1、Mechanical properties of hydroxyl functionalized chlorinated polyethylene prepared by in situ chlorinating graft copolymerizationYingying Sun & Gengping Wan & Baoxing Wang & Jiruo Zhao & Ying FengReceived

2、: 21 January 2008 /Accepted: 3 June 2008 /Published online: 4 July 2008 # Springer Science + Business Media B.V. 2008Abstract A graft copolymer composed of poly (2-hydroxy ethyl acrylate) (PHEA) as branched chains and ch

3、lorinated polyethylene (CPE) as backbone, CPE-cg-HEA, was synthesized by in situ chlorinating graft copolymerization (ISCGC). The polymer has special molecular structure with short graft chains and abundant branched poin

4、ts. The mechanical properties of CPE-cg-HEA were studied by tensile testing, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA). The morphologies of tensile fractured surfaces for CPE and CPE-cg-H

5、EA were investigated by scanning electron microscope (SEM). The testing results indicated the mechanical properties of the in situ chlorinating graft copolymers have greatly improved compared with CPE with about the same

6、 chlorine content. Particularly, there was a broad plateau on the stress–strain curve of the graft copolymer, which meant a high elastic- like deformation.Keywords CPE-cg-HEA . Functionalization .Mechanical properties .

7、Stress–strain curve .In situ chlorinating graft copolymerizationAbbreviations HEA 2-hydroxy ethyl acrylate CPE chlorinated polyethylene ISCGC in situ chlorinating graft copolymerization CPE-cg-HEA polyethylene in situ ch

8、lorinating graft 2-hydroxy ethyl acrylate DSC differential scanning calorimetry DMA dynamic mechanical analysisSEM scanning electron microscope HDPE high-density polyethylene GD Graft degree GPC gel permeation chromatogr

9、aphy WAXD wide-angle x-ray diffraction Tg glass transition temperature E’ storage modulus tanδ loss tangentIntroductionIn order to extend the application of chlorinated polyethylene (CPE) or obtain polymers with special

10、use, CPE needs to be modified by physical or chemical methods. There are many reports in recent years about the modification of CPE. Examples of such modification include adding chlorinated paraffin, a hindered phenol co

11、mpound and organic com- pounds etc. to obtain both good damping property and high stiffness [1–6]. By multicomponent mechanical blending technology, a water-swellable elastomer which is compati- bilized with graft copoly

12、mers has been prepared using CPE and poly(acrylic acid–acrylic amide) as the chief materials and an amphiphilic graft copolymer as the compatibilizer [7]. Carbon black(CB)as reinforcing filler is also filled into CPE for

13、 obtaining good properties. For binary systems of CPE and CB, oxidized CB gives a high modulus at low strain amplitude [8]. Because both polyurethane and CPE have polar functional groups which may interact to form interc

14、hain cross-links on heating, blends of polyurethane and chlorinated polyethylene elastomer have been prepared to obtain better performance properties through interchain cross-linking reaction [9]. One of the typical chem

15、ical modifications basing on CPE is the preparation of chlor-J Polym Res (2009) 16:165–172DOI 10.1007/s10965-008-9214-2Y. Sun: G. Wan: B. Wang: J. Zhao (*): Y. Feng Key Laboratory of Rubber-Plastics, Ministry of Educatio

16、n, Qingdao University of Science and Technology, Qingdao 266042, People’s Republic of China e-mail: jiruozhao@qust.edu.cnsupplied by Qingdao Sodium Silicate Co. Ltd, China. Chlorinated Polyethylene and the graft copolyme

17、r (CPE-cg- HEA) were prepared by the author in laboratory. Graft degree (GD) of CPE-cg-HEA is determined by 1H-NMR spectros- copy. The determining details of graft copolymerization of CPE-cg-HEA are going to be published

18、 elsewhere.The synthesis of CPE-cg-HEAISCGC was carried out [18] in a 500-ml round bottom three-necked flask equipped with a vane stirrer, a thermometer, and a gas delivery tube. 50 g HDPE and a certain amount of HEA mon

19、omers were added into the flask. It was stirred around 30-min to make HDPE and HEA sufficiently mixed. Then appropriate amount of silicon dioxide was added to avoid the agglomeration of PE. The reaction mixture was deaer

20、ated by nitrogen (N2) at about 40°C for 15 min to eliminate oxygen gas (O2). Then chlorine was introduced into the reactor. The reaction was initiated. The reaction temperature was elevated as the reaction proceeded

21、 and was kept in 80± 2°C before the chlorine content reached 17%, and then was raised to certain temperature(below 140°C) through the reaction process. The reaction process was indicated by the amount of h

22、ydrogen chloride (HCl) released from the reaction system. The chlorine gas was stopped and the reaction was terminated when the desired chlorine content was reached. The system was cooled down to below100°C. The chl

23、orine gas in the reactor was drawn out by vacuum and then air was let into the reactor. The vacuum and air influx operations were performed alternately some times to ensure the residual chlorine cleaned out completely. S

24、ynthetic scheme for the preparation of CPE-cg-HEA is shown in Fig. 1.Differential scanning calorimetry (DSC)DSC measurements were carried out with a PerkinElmer DSC-7 calorimeter. The samples were heated from ?70 to 150&

25、#176;C at a heating rate of 10°C/min to investigate the glass transition temperature of polymers. The tests were carried out under a nitrogen flow and a sample of 9 to 12 mg was used.Dynamic mechanical analysis (DMA

26、)The dynamic mechanical properties of various samples were determined with a dynamic mechanical analyzer (NETZSCH-DMA242), using a dynamic tensile mode in a rang of ?100°C to 120°C at a constant frequency of 15

27、.6 Hz and a heating rate of 3°C/min.Scanning electron microscope (SEM)SEM (JEOL JSM-6700F) was used to study the morphologies of fracture surfaces obtained from tensile testing. The fracture surfaces were coated wit

28、h gold by JFC-1600 Auto Fine Coater and then examined by SEM.Mechanical propertiesTensile properties were measured with a GOTECH AI-7000M Universal Testing Machine at room temperature and 55% Relative Humidity (RH). The

29、tensile tests were performed at a crosshead speed of 500 mm/min. Reported values were the average values of five individual measurements.Results and discussionMechanical properties of CPE-cg-HEAThe structure of CPE-cg-HE

30、A was characterized by FT-IR, 1H-NMR, gel permeation chromatography (GPC) and0 200 400 600 8001284CPECPE-cg-HEAStress (MPa)Strain (%)16Fig. 2 Stress–strain curves of chlorinated polyethylene (CPE) [Cl% (Wt):36%] and poly

31、ethylene in situ chlorinating graft 2-hydroxy ethyl acrylate (CPE-cg-HEA) [Cl% (Wt):36.1%]Table 1 Mechanical properties of chlorinated polyethylene (CPE) and polyethylene in situ chlorinating graft 2-hydroxy ethyl acryla

32、te (CPE-cg-HEA)Samples Chlorine content (Wt%) Young’s modulus ( MPa) Tensile strength (MPa) Elongation at break ( %) Hardness (Shore A )CPE 36.0 1.70 9.43 647 75 CPE-cg-HEA 36.1 0.70 14.8 801 71Hydroxyl functionalized ch

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