Properties of polystyrene/poly(dimethyl siloxane) blends partially compatibilized with star polymers containing a γ-cyclodextrin core and polystyrene arms

• Published in: Polymer (Guilford) 2010-11, Vol.51 (25), p.6013-6020
• Main Authors: Busche, Brad J., Tonelli, Alan E., Balik, C. Maurice
• Format: Article
• Language: English
• Subjects: Applied sciences; Blends; Compatibilization; Exact sciences and technology; Inorganic and organomineral polymers; Organic polymers; Physicochemistry of polymers; Properties and characterization; Rheology and viscoelasticity; γ-CD-star polymer
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2010.10.024

A star polymer with a γ-CD core and PS arms (CD-star) is used to partially compatibilize blends of the immiscible polymers polystyrene (PS) and poly(dimethylsiloxane) (PDMS). The mechanism of compatibilization is threading of the CD core by PDMS and subsequent solubilization in the PS matrix facilitated by the star arms. Films cast from clear solutions in chloroform exhibit large wispy PDMS domains, indicating that some dethreading of CD-star and agglomeration of PDMS takes place during the slow process of solvent evaporation. However, DSC and DMA data show that partial compatibilization takes place, as evidenced by a shift in the PS and PDMS Tgs toward each other. The shift in PS Tg is greater when CD-star is present compared to samples without CD-star. PDMS also tends to leach out of the solution-cast films during solvent evaporation and post-processing of the films. The amount of retained PDMS is significantly increased when CD-star is present. The DMA data also show that PDMS has a lower molecular mobility when CD-star is present. [Display omitted]