English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Long chain branched polypropylene random copolymers (LCB-PPRs) were prepared  reactive extrusion with the addition of dicumyl peroxide (DCP) and various amounts of 1,6-hexanediol diacrylate (HDDA) into PPR. Fourier transform infrared spectrometer (FTIR) was applied to confirm the existence of branching and investigate the grafting degree for the modified PPRs. Melt flow index (MFI) and oscillatory shear rheological properties including complex viscosity, storage modulus, loss tangent and the Cole-Cole plots were studied to differentiate the LCB-PPRs from linear PPR. Differential scanning calorimetry (DSC) and polarized light microscopy (PLM) were used to study the melting and crystallization behavior and the spherulite morphology, respectively. Qualitative and quantitative analyses of rheological curves demonstrated the existence of LCB. The effect of the LCB on crystalline morphology, crystallization behavior and molecular mobility, and, thereby, the mechanical properties were studied and analyzed. Due to the entanglements between molecular chains and the nucleating effect of LCB, LCB-PPRs showed higher crystallization temperature and crystallinity, higher crystallization rate, more uniformly dispersed and much smaller crystallite compared with virgin PPR, thus giving rise to significantly improve impact strength. Moreover, the LCB-PPRs exhibited the improved yield strength. The mobility of the molecular chain segments, as demonstrated by dynamic mechanical analysis (DMA), was improved for the modified PPRs, which also contributed to the improvement of their mechanical properties.

Effect of long chain branching on the rheological behavior, crystallization and mechanical properties of polypropylene random copolymer