以基于Cr系催化剂、不同己烯含量的管材用乙烯己烯共聚物为研究对象,应用1H固体NMR技术测定了其室温下的相结构参数以及不同温度下的相结构变化.研究发现,随着共聚单体含量的增加,NMR结晶相组分的含量降低,界面区和无定形区组分含量增加,且两者在NMR测定的长周期中所占的比例也增加.提出了以界面区含量和无定形区含量的比例随温度的变化作为定性判断非晶区中链段运动受限程度的依据.此外,采用相同的1H固体NMR技术研究了不同耐压等级聚乙烯管材料基体树脂的聚集态结构.发现室温下随着管材料耐压等级的增加,结晶相组分含量减少而其他两组分含量增加,且NMR测定的长周期中结晶相组分所占比例降低而其他两组分比例升高.实验结果证明,上述定性判断非晶区中链段运动受限程度的判据与材料的耐压等级有较好的对应关系.
参考文献
| [1] | Y.Huang,N.Brown,Dependence of slow crack growth in polyethylene on butyl branch density:Morphology and theory,J Polym Sci Part B:Polym Phys,29,129(1991) |
| [2] | J.T.Yeh,J.Runt,Fatigue crack propagation in highdensity polyethylene,J.Polym Sci Part B:Polym Phys,29,371(1991) |
| [3] | T.Cho,E.Shin,W.Jeong,B.Heck,R.Graf,G.Strobl,H.Spiess,D.Yoon,Effects of comonomers on lamellar and noncrystalline microstructure of ethylene copolymers,Macromol Rapid Commun,27,322(2006) |
| [4] | R.Seguela,Critical review of the molecular topology of semicrystalline polymers:The origin and assessment of intercrystalline tie molecules and chain entanglements,J.Polym.Sci.Part B:Polym.Phys.,43,1729(2005) |
| [5] | C.Hedesiu,D.Demco,R.Kleppinger,A.Buda,B.Blümich,K.Remerie,V.M.Litvinov,The effect of temperature and annealing on the phase composition,molecular mobility and the thickness of domains in high-density polyethylene,Polymer,48,763(2007) |
| [6] | D.Demco,A.Johansson,J.Tegenfeldt,Proton spin diffusion for spatial heterogeneity and morphology investigations of polymers,Solid State Nucl.Magn.Reson.,4,13(1995) |
| [7] | B.Blümich,NMR Imaging of Materials (Oxford,Clarendon Press,2000) |
| [8] | B.Wunderlich,Macromolecular Physics,Vol.3,Crystal Melting (New York,Academic Press,1980) |
| [9] | Z.S.Mo,H.F.Zhang,Structure of Crystalline Polymers by X-ray Diffraction (Beijing,The Science Press of China,2003) |
| [10] | D.Massiot,F.Fayon,M.Capron,L.King,S.L.Calvé,B.Alonso,J.O.Durand,B.Bujoli,Z.Gan,G.Hoatson,Modelling one-and two-dimensional solid-state NMR spectra,Magn.Reson.Chem.,40,70(2002) |
| [11] | A.Buda,D.Demco,M.Bertmer,B.Blümich,B.Reining,H.Keul,H.H(o)cker,Domain sizes in heterogeneous polymers by spin diffusion using single-quantum and doublequantum dipolar filters,Solid State Nucl.Magn.Reson.,24,39(2003) |
| [12] | X.W.Yan,J.D.Wang,X.H.Ren,Y.R.Yang,B.B Jiang,M.A.Voda,M.Bertmer,M.Stapf,Phase structures of nascent polyethylene powder studied by wideline proton NMR,Chin.J.Chem.,25,863(2007) |
| [13] | R.G.Alamo,L.Mandelkern.,The crystallization behavior of random copolymers of ethylene,Thermochim.Acta,238,155(1994) |
| [14] | J.R.Isasi,J.S.Haigh,J.T.Graham,L.Mandelkern,R.G.Alamo,Some aspects of the crystallization of ethylene copolymers,Polymer,41,8813(2000) |
| [15] | R.M.Patel,K.Sehanobish,P.Jain,S.P.Chum,G.W.Knight,Theoretical prediction of tie-chain concentration and its characterization using postyield response,J.Appl.Poly.Sci.,60,749(1996) |
上一张
下一张
上一张
下一张
计量
- 下载量()
- 访问量()
文章评分
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%