Improved water barrier properties of polylactic acid films with an amorphous hydrogenated carbon (a-C:H) coating

Poly(lactic acid) biocomposites with mango waste and organo‐montmorillonite for packaging

“…The PLA FTIR spectrum is displayed in Figure . It reveals the main PLA bands at 2996 cm −1 and 2945 cm −1 , attributed to asymmetric stretching vibrations of CH 3 groups; 1748 cm −1 , related to stretching and bending vibrations of CO groups; 1453 cm −1 , attributed to asymmetric deformation vibrations of CH 3 ; 1382 cm −1 and 1359 cm −1 , attributed to symmetric deformation vibrations of CH 3 ; 1303 cm −1 , 1266 cm −1 , and 1206 cm −1 (shoulder), related to deformation vibrations of tertiary carbons; 1180 cm −1 , attributed to C─O stretching vibrations of lactide units or to C─O─C asymmetric stretching; 1127 cm −1 , attributed to C─H (of CH 3 groups) rocking mode; 1081 cm −1 and 1043 cm −1 , where the first one is related to C─O─C asymmetric stretching and the second to C─CH 3 stretching vibration, or both could be due to rocking vibrations of CH 3 ; 956 cm −1 , related to stretching of C─C bonds; 869 cm −1 and 752 cm −1 , attributed to ─CH 2 ─ rocking vibrations; and 705 cm −1 and 668 cm −1 …”

Antimicrobial activity of nisin‐coated polylactic acid film facilitated by cold plasma treatment

“…Figure (a) reveals a broad –OH stretching band between 3680 and 3458 cm −1 and an aliphatic –C–H stretching band between 3000 and 2750 cm −1 , and the peak at 1748 cm −1 could be related to the C=O stretching of ester groups. The peaks at 1452 and 1382 cm −1 were assigned to the deformation vibrations of the CH 3 group, and the three peaks at 1181, 1080, and 1043 cm −1 were attributed to C–O stretching vibration absorptions [Figure (b)] . With an increase in CPT time, the peak of the CH 3 group at 2989 cm −1 became intense, whereas the peaks between 2945 and 2850 cm −1 disappeared.…”

Reduced graphene oxide as a water, carbon dioxide and oxygen barrier in plasticized poly(vinyl chloride) films

“…We recently used FTIR-ATR spectroscopy to show that a 120 nm thick amorphous hydrogenated carbon (a:C-H) layer deposited with radio-frequency plasma-enhanced CVD on 50 mm thick poly(lactic acid) lms (PLA) decreased the water uptake of PLA by 55% aer a contact time of 24 h, and even more at shorter times. 64 The FTIR-ATR technique was previously used for studying the water uptake of plasticized PVC, 49,65,66 poly(acrylate) 67,68 and silicone rubber based ion-selective membranes 66,68,69 to prevent the detrimental water layer or pool formation at the interfaces of potentiometric SCISEs. [69][70][71] Although plasticized PVC is rather hydrophobic, we have shown with FTIR-ATR measurements that it cannot prevent the water layer formation 49,66 that results in the potential instability and irreproducibility of these devices.…”