testing method :
 1. Membrane disintegration time :
 According to the MSTM-205 disintegration protocol, the cold water film disintegration characteristics of different sodium caseinate/polyvinyl alcohol homopolymer water-soluble films were determined in demineralized water at 10°C. Within this test, the average membrane rupture time (in seconds) has been recorded for 3 replicates.
 2. Membrane dissolution time :
 The cold water solubility characteristics of different sodium caseinate/polyvinyl alcohol homopolymer based water-soluble films were determined in demineralized water at 20°C by Monosol using a dissolution chamber according to MSTM-119 Standard Test Method for Residues. In this test, the average % dissolved film after 10 minutes of immersion in water has been recorded for 3 replicates of the film.
 3. Tensile strain at break % :
 The water soluble film test samples were analyzed for % tensile strain at break as follows. This procedure involves determining the % tensile strain at break according to ASTM D 882 ("Standard Test Method for Tensile Properties of Thin Plastic Sheeting"). Film data was collected using an INSTRON tensile testing apparatus (Model 5544 Tensile Tester or equivalent - Instron Industrial Products, 825 University Ave., Norwood, MA 02062-2643). Five specimens are tested, each with a reliable cutting tool (eg, JDC Precision Specimen Cutter, Models 1-10, available from Thwing Albert Instrument Company, Philadelphia, PA U.S.A.) ) cut to ensure dimensional stability and reproducibility. Water soluble films were preconditioned to test ambient conditions for 24 hours. Testing was performed in a standard laboratory atmosphere of 20°C and 33% relative humidity. A 1 inch wide (2.54 cm) sample of a single film sheet with a thickness of 3.0 +/- 0.15 mils (or 76.2 +/- 3.8 [mu]m) was prepared. The samples were then transferred to the INSTRON tensile testing machine for testing. Prepare the tensile testing machine according to the manufacturer's instructions, equipped with a 500N load cell and calibrated. The jig and face were assembled correctly (INSTRON jig has a model 2702-032 face or equivalent, the face has a rubber coating and is 25mm wide). The samples were mounted in a tensile testing machine, elongated at a rate of 1 N/min, and analyzed to determine the stress-strain curve. The % tensile strain at break is extracted from the stress-strain curve, for example, the data is the % tensile strain at break of the film (higher the better, preferably >150%, more preferably >200%, most preferably >250 %). Calculate and report the average of 3 samples.
 Test material:
 Starting polymer material:
 · PVA homopolymer: Mowiol 18/88 (ex Sigma Aldrich)
 Sodium Caseinate: Sodium caseinate from milk (ex Sigma Aldrich)
 Polymer Blends:
 100% sodium caseinate
 80/20 weight ratio sodium caseinate/PVA homopolymer
 60/40 weight ratio sodium caseinate/PVA homopolymer
 50/50 weight ratio sodium caseinate/PVA homopolymer
 40/80 weight ratio sodium caseinate/PVA homopolymer
 20/80 weight ratio sodium caseinate/PVA homopolymer
 100% PVA homopolymer
 Water-soluble films from the corresponding polymer blends have been prepared as detailed herein:
 • Dosing the polymer resin/powder in demineralized water to make a 15% solution. Add plasticizer and other additives according to the ratio. The mixture was stirred at 200 rpm in a 50 ml glass bottle. The solution was heated under reflux at 80°C in a propylene glycol bath for 4 hours.
 · Fully dissolve the polymer in water to make a homogeneous solution, and drive out air bubbles by ultrasound and vacuum;
 Pour the homogeneous solution onto a treated glass support (ClSi(CH) 3 ) 3 , in CHCl 3 middle) on;
Spread the solution into thin layers using a film applicator with a wet gap ranging from 250 μm to 350 μm;
 · The resulting membrane was left to stand overnight at ambient conditions (22°C, 35% RH);
 • Peel the dried film from the support.
 Test Results :
 Table 1
 *Not measured