Gumede Thandi P, Luyt Adriaan S, Tercjak Agnieszka, Müller Alejandro J
Department of Chemistry, University of the Free State (Qwaqwa Campus), Private Bag X13, Phuthaditjhaba 9866, South Africa.
Central University of Technology, Department of Life Sciences, Private Bag X20539, Bloemfontein 9300, South Africa.
Polymers (Basel). 2019 Apr 15;11(4):682. doi: 10.3390/polym11040682.
In this work, the 70/30 and 30/70 w/w polycaprolactone (PCL)/polybutylene succinate (PBS) blends and their corresponding PCL/PBS/(polycarbonate (PC)/multiwalled carbon nanotubes (MWCNTs) masterbatch) nanocomposites were prepared in a twin-screw extruder. The nanocomposites contained 1.0 and 4.0 wt% MWCNTs. The blends showed a sea-island morphology typical of immiscible blends. For the nanocomposites, three phases were formed: (i) The matrix (either PCL- or PBS-rich phase depending on the composition), (ii) dispersed polymer droplets of small size (either PCL- or PBS-rich phase depending on the composition), and (iii) dispersed aggregates of tens of micron sizes identified as PC/MWCNTs masterbatch. Atomic force microscopy (AFM) results showed that although most MWCNTs were located in the PC dispersed phase, some of them migrated to the polymer matrix. This is due to the partial miscibility and intimate contact at the interfaces between blend components. Non-isothermal differential scanning calorimetry (DSC) scans for the PCL/PBS blends showed an increase in the crystallization temperature () of the PCL-rich phase indicating a nucleation effect caused by the PBS-rich phase. For the nanocomposites, there was a decrease in values. This was attributed to a competition between two effects: (1) The partial miscibility of the PC-rich and the PCL-rich and PBS-rich phases, and (2) the nucleation effect of the MWCNTs. The decrease in values indicated that miscibility was the dominating effect. Isothermal crystallization results showed that the nanocomposites crystallized slower than the neat blends and the homopolymers. The introduction of the masterbatch generally increased the thermal conductivity of the blend nanocomposites and affected the mechanical properties.
在本研究中，通过双螺杆挤出机制备了质量比为70/30和30/70的聚己内酯（PCL）/聚丁二酸丁二醇酯（PBS）共混物及其相应的PCL/PBS/（聚碳酸酯（PC）/多壁碳纳米管（MWCNTs）母料）纳米复合材料。纳米复合材料中MWCNTs的含量为1.0 wt%和4.0 wt%。共混物呈现出不相容共混物典型的海岛形态。对于纳米复合材料，形成了三相：（i）基体（根据组成，为富含PCL或PBS的相），（ii）小尺寸的分散聚合物液滴（根据组成，为富含PCL或PBS的相），以及（iii）确定为PC/MWCNTs母料的数十微米尺寸的分散聚集体。原子力显微镜（AFM）结果表明，尽管大多数MWCNTs位于PC分散相中，但其中一些迁移到了聚合物基体中。这是由于共混物组分之间在界面处的部分互溶性和紧密接触。PCL/PBS共混物的非等温差示扫描量热法（DSC）扫描显示，富含PCL相的结晶温度（）升高，表明富含PBS相引起了成核效应。对于纳米复合材料，值有所降低。这归因于两种效应之间的竞争：（1）富含PC的相与富含PCL和富含PBS的相之间的部分互溶性，以及（2）MWCNTs的成核效应。值的降低表明互溶性是主导效应。等温结晶结果表明，纳米复合材料的结晶速度比纯共混物和均聚物慢。母料 的引入通常提高了共混物纳米复合材料的热导率，并影响了机械性能。
