Table 1.
Physical properties of polymers applied in packaging and food packaging.
| Polymer | Packaging Types | Thermal | Mechanical | Permeability | |||||
|---|---|---|---|---|---|---|---|---|---|
| Tg (°C) | Tm (°C) | T (MPa) | εB (%) | OP | H2O: WVTR (g/m2/day) | O2 (g/m2/day) |
CO2 (ml μm m−2 day−1 atm−1) |
||
| PET | Bottles, microwaveable and ovenable trays, boil in-the-bag products | 70–87 | 243–268 | 48–72 | 20–300 | ++ | 15–20 | 100–150 | 300–600 |
| HDPE | Jars and other rigid containers, pallets, films, or layers for dry food | −125 to −90 | 135 | 22–31 | 100 ≥ 1000 | +++ | 7–10 | 1600–2000 | 12,000–14,000 |
| PVC | Wrapping films, bottles, trays, containers | 60–100 | n.d. | 40–51 | 40–75 | ++ | 0.5–1.0 | 2–4 | 400–10,000 |
| LDPE | Films (wrapping, carrier bags, pouches), bottles | −125 to −100 | 112–135 | 8–31 | 200–900 | ++ | 10–20 | 6500–8500 | 20,000–40,000 |
| PP | Cups and containers for frozen and microwaveable food, lids, thin-walled containers (yoghurt) | −10 | 167–177 | 31–41 | 100–600 | + | 10–12 | 3500–4500 | 10,000–14,000 |
| PS | Disposable cups, plates and trays, boxes (egg cartons), rigid containers (yoghurt) | 100 | n.d | 35–51 | 1–4 | ++ | 4500–6000 | 14,000–30,000 | |
| PA | flexible packaging of perishable food, such as cheese and meat | 50–60 | 220 | 40–52 | 5–10 | ++ | 300–400 | 50–75 | n.d |
| PVA | Films for moisture barrier, confectionery products | 70–75 | 215–220 | 25–30 | 220–250 | ++ | n.d. | n.d. | n.d |
| EVOH | Thin films for dry/fatty food, multilayer | 60–65 | 180–150 | 45–110 | 180–250 | +++ | 1000 | 0.5 | n.d |
Tg—glass transition temperature; Tm—melting temperature; T—tensile strength; εB—elongation at break (%); OP—overall optical properties including haze, gloss, and transmission of visible light; permeability (H2O, water vapor; O2, oxygen gas; CO2, carbon dioxide gas) for polymeric films.
Oxygen permeability and water vapor transmission rate were evaluated (WVTR) in (g/m2/24 h) in tropical conditions (90% Relative Humidity (RH) at 38 °C).
n.d.: not defined. +: low. ++: medium. +++: high. Polyethylene terephthalate (PET); high density polyethylene (HDPE); polyvinyl chloride (PVC); low density polyethylene (LDPE); polypropylene (PP); polystyrene (PS); polyamide (PA); poly (vinyl alcohol) (PVA); poly (vinyl alcohol-co-ethylene) (EVOH).