The effect of cellulose nanofibers on the crystallinity and nanostructure of poly(lactic acid) composites

The Influence of Pre‐Electrospinning Plasma Treatment on Physicochemical Characteristics of PLA Nanofibers

“…XRD patterns of PLA nanofibers electrospun from pristine and differently prepared plasma‐modified PLA solutions are shown in Figure . A characteristic α‐crystal peak at 2θ = 17.15°, corresponding to (110)/(200) planes, together with a broad peak in the range of 2θ = 10°–25° attributed to an amorphous phase, is observed for all untreated nanofibers with different polymer concentrations (5d) . The mentioned broad peak and the α‐peak confirm the semi‐crystalline structure of the nanofibers electrospun from pristine PLA solutions and is in good agreement with the literature .…”

“…After PEPT, the α‐peak disappears and the broad peak, corresponding to the PLA amorphous structure, decreases with increasing plasma treatment time, argon flow rate, applied voltage, and PLA concentration. In addition, the presence of another reflection peak around 2θ = 31.56°, corresponding to the (207) plane, is identified for nanofibers electrospun from plasma‐treated solutions, which is associated with the β‐crystalline structure which is more disordered than the α‐crystalline phase . The formation of β‐phase for plasma‐treated samples which is identified in XRD patterns, is in agreement with the variations of the melting peak observed in DSC results.…”

“…Polymer concentration does not have a considerable effect on Δ H m . Although a simple melting peak typical of the α‐crystalline phase is observed for all samples, small additional humps are also appearing just before and after the melting peak for the nanofibers obtained from plasma‐treated solutions, showing the presence of more than one crystalline form (red boxes in Figure S3, Supporting Information) . Interestingly, these humps do not appear for the plasma‐treated PLA cast layer, as will be shown further in this study (Figure S6a, Supporting Information).…”

“…The shift in T c peak toward higher values after PEPT coincides with a reduction in the area under this peak (Δ H c , Figure ), showing restructuring of certain crystalline structures, generally related to thinner or less perfect crystals formed during the fabrication of nanofibers from plasma‐treated spinning solutions . The higher values of T c for plasma‐treated samples as compared to untreated samples could also be attributed to the improved interfacial adhesion energy that hinders crystallization during electrospinning .…”

Blends of Poly (L-Lactic Acid) and Glucose Prepared from Mixture Solution

“…PLLA isα-crystalline structure with the strongest peaks at 2θ of 16.52°, as well as other peaks at 14.90°, 19.21° and 22.45° with a crystallinity of 20.8%. The XRD curve of PLLA-Glu blend with PLLA/Glu ratio of 9:1 is similar to that of PLLA [9,12] . This result is probably owing to the strong interaction between PLLA and glucose, which may hinder the crystallization process of glucose and cause imperfect crystal of PLLA, as already demonstrated by DSC.…”