The degradable and magnetic PLA/Fe3O4 melt-blown materials for air filtration application were prepared by melt-blowing process using the PLA/Fe3O4 composites with different components obtained by melt-mixing as the masterbatch.

In this work, the blend films of poly(lactic acid) (PLA) and poly(ε-caprolactone) (PCL) were prepared by the solvent casting method. The influence of PCL content and compatibilizer on the structure, tensile and barrier properties was studied. The results indicated that PCL showed good dispersion in PLA matrix as tributyl citrate (TBC) was added as a compatibilizer. PCL showed a promotion effect on the crystallinity of PLA/PCL films. The compatibility of PLA and PCL was improved by TBC. The tensile modulus and the elongation at break of PLA/PCL films increased to various extents due to the input of PCL and TBC compared to pure PLA film. The improvement of oxygen and water vapor barrier properties of the blend films were provided and depended on the content of PCL and the appearance of TBC. The transparency of the blend films decreased with the increase of the PCL content.

The thermal properties and morphological characterisation of isotactic polypropylene (iPP) homopolymer and its blends with low molecular low modulus polypropylene (LMPP) were studied. Firstly blends were prepared with variant LMPP contents, and their properties were characterised using SEM, DSC, XRD, and DMA. Later the mechanical properties of iPP/LMPP blend fibres were investigated. SEM results showed that the iPP/LMPP blends produced smoother surfaces when the LMPP content was increased, as well as the miscibility. All the Tg values with different LMPP percentages were in-between pure iPP and LMPP. The XRD results indicated the LMPP percentage decreased along with the degree of crystallinity of the iPP/LMPP blends (5% to 15%), which increased and then decreased as compared to pure iPP. The elongation at break increased when the LMPP content increased, with the maximum breaking elongation of the LMPP 25% blend reaching 12.95%, which showed great stretch-ability, whereas the elastic modulus of iPP/LMPP blends decreased.

Poly(lactic acid) melt‐blown (MB) webs were melt‐spun by MB processing of poly(lactic acid) and poly(lactic acid)/filler blends. The effect of tourmaline particles on the structure, morphology, mechanical and filtration properties of poly(lactic acid) blends, and MB webs were reported. The blends and MB webs were characterized using differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WXRD), scanning electron microscopy (SEM), and pore size meter (PSM). The degree of crystallinity of blends with tourmaline particles was more than that of poly(lactic acid) alone. SEM micrographs revealed a good dispersion of the additive in the blends and fiber webs. The tourmaline particles offered some benefits to the mechanical properties of the MB web. MB web samples with tourmaline had larger pore size, high surface charge density, and higher filtration efficiency. POLYM. COMPOS., 36:264–271, 2015. © 2014 Society of Plastics Engineers

Optimization of the mechanical and thermal properties of isotactic polypropylene (iPP) homopolymer blended with relatively new low molecular low modulus polypropylene (LMPP) at different blend ratios was carried out via surface response methodology (RSM). Regression equations for the prediction of optimal conditions were achieved considering eight individual parameters: naming, elongation at break, tensile strength and elastic modulus, crystallization temperature (TC), first melting temperatures (TM1), heat fusion (Hf), crystallinity, and melt flow rate (MFR), which were measured as responses for the design of experiment (DOE). The adjusted and predicted correlation coefficient (R2) shows good agreement between the actual and the predicted values. To confirm the optimal values from the response model, supplementary experiments as a performance evaluation were conducted, posing better operational conditions. It has been confirmed that the RSM model was adequate to reflect the predicted optimization. The results suggest that the addition of LMPP into iPP could effectively enhance the functionality and processability of blend fibres if correctly proportioned.

With aim to improve the mechanical and thermal properties of poly (lactic acid) (PLA) melt-blown nonwovens (MBs), polyamide 11 (PA11) was melt blended with PLA at the weight proportions of PLA/PA11 (95/5, 90/10, 85/15, 80/20), and the corresponding PLA/PA11 MBs were also manufactured. The crystallization, thermal and rheological behaviors of PLA/PA11 blends were investigated. PLA/PA11 MBs were also characterized by morphology and mechanical properties. The results indicated that PA11, as globular dispersed phases, formed confined crystals and could improve the thermal stability of PLA matrix. The viscosity of PLA/PA11 blends was slightly increased but the rheological behaviors of “shear-thinning” kept unchanged in comparison with PLA. The average diameter of PLA/PA11 MB fibers was slightly increased, whereas the toughness of PLA/PA11 MBs including the strength and elongation were efficiently enhanced compared with those of PLA MBs.

The properties of fibers were significantly affected by drawing during the spunbond process. In this paper, the influence of drawing pressure on the properties of spunbonded PET/PA6 hollow pie wedge bicomponent filaments was studied, and their performance was characterized by differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, Beion F6 fiber fineness tester, and single fiber strength tester. The hollow pie wedge bicomponent fiber had a distinct interface between the two polymers due to poor compatibility. With increasing of drawing pressure, diameter of the fibers reduced regularly. When the drawing pressure increased, both the degree of crystallinity and orientation of bicomponent fibers enhanced, and the melting point of polyester component increased as well. Furthermore, with increasing of drawing pressure, the breaking strength of the fibers increased, but the breaking elongation and linear density decreased.

To develop fully biodegradable and reinforced poly(lactic acid) (PLA) melt-blown nonwovens (MBs) for separation and filtration, PLA/aminated halloysite nanotubes (PLA/A-HNTs) MBs were prepared using PLA/A-HNTs master-batches, compatibilized by dual-monomer glycidyl methacrylate-styrene (St-co-GMA) melt-grafted PLA (PLA-g-(St-co-GMA)). The morphology, crystallization, pore size distribution, filtration performance, and mechanical properties of PLA/PLA-g-(St-co-GMA)/A-HNTs MBs were characterized. The results indicated that PLA/PLA-g-(St-co-GMA)/A-HNT MBs could be successfully manufactured, with well dispersed A-HNTs in PLA MB fibers due to improved compatibility by PLA-g-(St-co-GMA). Incorporation of A-HNTs and PLA-g-(St-co-GMA) slightly increased the average diameter and pore size of PLA MBs. A-HNTs increased the crystallinity degree of PLA MBs, while the crystal forms remained unchanged. In comparison with PLA MBs, the tensile strengths of PLA/PLA-g-(St-co-GMA)/A-HNTs MBs were enhanced but the elongation decreased. PLA/PLA-g-(St-co-GMA)/A-HNT MBs could obtain higher filtration efficiency than neat PLA MBs.