Biobased Polyester‐Amide/Cellulose Nanocrystal Nanocomposites for Food Packaging

Abstract

The worldwide plastic waste production is steadily increasing, since the use of polymeric materials continues to rise. One area of particular high plastic consumption is food packaging. Flexible and rigid packaging films are typically made from petrochemical‐sourced polymers, which are utilized because of their low cost, ductility, melt‐processability, and gas barrier properties, but a major downside is their inability to biodegrade in a reasonable time. Packaging‐relevant properties of nanocomposites based on polyester‐amides (PEAs) are reported, which are chosen on account of their tunable crystallinity, biobased starting materials, and biodegradability. These polymers are synthesized via melt polycondensation of a building block made from caprolactone and 1,4‐diaminobutane, with the addition of 1,4‐butanediol and dimethyl adipate. The fraction of the amide segment is varied between 25 and 75 mol%. The oxygen transmission rate (O2TR) drops upon increasing the amide content from 1.6 × 105 to 2.9 × 10−4 cm3 m−2 d−1 on account of increasing crystallinity. In order to improve the gas barrier properties further, nanocomposites of the PEAs and 1–10 wt% cellulose nanocrystals (CNCs) are prepared. These nanocomposites have indeed lower O2TR values than the neat PEAs, with reductions of as much as 50% for a CNC content of 10 wt%.

Impacts of cellulose nanofibers on the morphological behavior and dynamic mechanical thermal properties of extruded polylactic acid/cellulose nanofibril nanocomposite foam

“…[30][31][32] One way to improve the properties of polymer composites is to use nanoparticles. 33 Loading inorganic particles can improve many drawbacks of PLA such that enhance the strength of the PLA melt, improve PLA foaming behavior, and accelerate the kinetics of PLA crystallization. 34 It has also been proposed that loading crystal nucleating agents are the reason for crystallization takes place at a higher temperature or a faster cooling rate.…”

Assessing Knowledge and Use Practices of Plastic Food Packaging among Young Adults in South Africa: Concerns about Chemicals and Health

“…A recent review [11] confirmed that consumers are aware and informed of the need to avoid or reduce their use of plastic packaging materials. However, this is not always possible in practice, since the use of plastic for packaging has increased, and various food and beverage packaging applications and polymer modifications have been developed [12,13].…”

Finite Element Analysis of Gas Diffusion in Polymer Nanocomposite Systems Containing Rod-like Nanofillers

“…For fillers with surface modifications based either on ionic exchange or grafting of molecules of different chain lengths and mobilities, the existence and significant role played by this third phase on the barrier properties have been experimentally proven [ 38 , 53 , 54 , 55 , 56 , 57 , 58 , 59 ]. In some cases, the barrier properties are enhanced by the presence of the interphase due to stronger filler–matrix interfacial interactions [ 32 , 35 , 60 , 61 , 62 ]. In other cases, increased mobility or a lack of packing density in the interphase region lead to degradation of the barrier effect [ 51 , 63 , 64 , 65 ].…”

“…Rader at al. [ 32 ] reported oxygen transmission rate (OTR) reductions of as much as 40% for a CNC content of 10 wt% within a bio-based polyester-amide (PEA) matrix. It was shown that the barrier enhancement was highly dependent on the composition of the PEA matrix but much less so on the CNC content.…”