Localization of MWCNTs in PET/LDPE blends
Localization of MWCNTs in PET/LDPE blends
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DOI：
10.1016/j.eurpolymj.2013.01.007
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发表时间：
2013-06-01
影响因子：
6
通讯作者：
McNally, Tony
中科院分区：
文献类型：
--
作者：
Cardinaud, Romain;McNally, Tony
研究了PET和LDPE的不混溶共混物中未官能化的MWCNT的定位作为共混比的函数，并且对于20：80的PET：LDPE共混物作为高达5重量%的MWCNT负载的函数。润湿系数的理论预测，显微镜检查，电导率测量，差示扫描量热法（DSC）和振荡流变学分析证实了多壁碳纳米管优先位于PET相。对于共混比变化且MWCNT含量保持恒定在2wt%的共混物，从40：60 PET：LDPE共混物的“液滴中的液滴”形态的形成中检测到相转化的开始。该共混物是半导电的（10（4）Ω cm），但当LDPE含量增加到80重量%时，MWCNTs被限制在孤立的PET液滴中，共混物的电阻率增加了11个数量级。随着MWCNT的加入，PET组分的结晶温度（T-c）和结晶含量（X-c）增加，但LDPE相的T-c和X-c不变。PET：LDPE共混物在低频（ω < 1 rad/s）下的熔体粘度随着PET共混物含量的增加而增加，因为当PET为连续相时，MWCNT容易分散在PET中。来自20：80 PET：LDPE共混物的Cole-Cole图的证据，其中MWCNT负载量增加至5重量%表明多壁碳纳米管对这种富含LDPE的共混物的流变响应几乎没有影响。然而，随着多壁碳纳米管在PET相中的凝聚，该共混物的熔体粘度增加，多壁碳纳米管在相之间的转移、分散和分布以及颗粒聚结变得更加困难。因此，在较高的多壁碳纳米管负载量，一些多壁碳纳米管保持在LDPE相或在共混物界面和电导率的显着增加。(C)2013爱思唯尔有限公司保留所有权利。
The localization of un-functionalized MWCNTs in immiscible blends of PET and LDPE was investigated as a function of blend ratio and for a 20:80 PET:LDPE blend as a function of MWCNT loading up to 5 wt%. Theoretical prediction of wetting coefficients, microscopic examination, electrical conductivity measurements, differential scanning calorimetry (DSC) and oscillatory rheology analysis confirmed the MWCNTs preferentially located to the PET phase. For blends where the blend ratio was varied and the MWCNT content kept constant at 2 wt.%, the onset of phase inversion was detected from the formation of a 'droplet in droplet' morphology for the 40:60 PET:LDPE blend. This blend was semi-conductive (10(4) Omega cm), but when the LDPE content was increased to 80 wt.%, the MWCNTs were confined to isolated PET droplets, the resistivity of the blend increased by 11 orders of magnitude. Crystallization temperature (T-c) and crystalline content (X-c) of the PET component increased, but T-c and X-c for the LDPE phase was unchanged with MWCNT addition. The melt viscosity of the PET:LDPE blend at low frequencies (omega < 1 rad/s) increased with increasing PET blend content as the MWCNTs were readily dispersed in PET when it was the continuous phase. Evidence from Cole-Cole plots for the 20:80 PET:LDPE blends with increasing MWCNT loading up to 5 wt.% showed the MWCNTs had little effect on the theological response of this LDPE rich blend. However, as more MWCNTs are condensed in the PET phase, the melt viscosity of this blend increased, MWCNT transfer between phases, dispersion and distribution, and, particle coalescence become more difficult. Therefore, at higher MWCNT loadings, some MWCNTs remain in the LDPE phase or at the blend interface and a significant increase in electrical conductivity was obtained. (C) 2013 Elsevier Ltd. All rights reserved.