Wanwei PVA 03-97(L) is a partially hydrolyzed polyvinyl alcohol characterized by a viscosity of
3.5–4.5 mPa·s (
4% aqueous solution,
20 °C,
DIN 53015), a saponification degree of
97.0 ± 1.0 mol%, a maximum ash content of
0.5%, and a pH of
5.0–7.0 (
4% solution). The low degree of polymerization (approximately
300) combined with near-fully hydrolyzed acetate groups results in a balance of cold-water insolubility, hot-water solubility above
75 °C, and film flexibility suitable for several manufacturing processes that demand rapid dissolution, controlled rheology, and tensile strength development. Material stored at relative humidity exceeding
60% requires pre-drying under dehumidified air at
60–65 °C for
4 hours to prevent silo bridging and dosage inaccuracies. The following sections delineate material use in downstream converting operations.
What Substitution Degree Minimizes Hairiness in High-Density Cotton Sizing?
On a Benninger Sizecoat 2 slasher processing
80/2 compact-spun cotton at a line speed of
95 m/min, the size bath is maintained at
90–92 °C with a solids content of
7.5–9.0 wt%, of which Wanwei PVA 03-97(L) constitutes
75–85% of the dry size blend alongside a medium-viscosity esterified starch. The size pickup target is
11.5–13.0% dry weight on yarn, achieving a breaking strength retention exceeding
92% per
ISO 2062 and a hairiness index reduction of
45–60% as measured on a Zweigle G567 Hairiness Tester. The low solution viscosity—typically
14–17 mPa·s (Brookfield LV, Spindle 1,
60 rpm,
90 °C)—facilitates penetration into the yarn core without excessive surface layering, diminishing the risk of size crusting on drying cylinders. The squeeze nip pressure is set to
12–15 kN/m at the pre-dry section; exceeding this range leads to starved penetration, while insufficient pressure elevates the wet pickup above
115%, causing energy penalty in the subsequent convection drying. Drying cylinder temperatures are profiled from
110 °C (entry) to
130 °C (middle) and tapered to
105 °C at exit to remain below the
150 °C threshold where thermo-oxidative discoloration of the PVA film initiates. Alkaline carryover from scouring, particularly sodium hydroxide residues exceeding
pH 9.5 in the rewet zone, catalyses ester hydrolysis and reduces film toughness; a neutralization rinse with acetic acid to
pH 7.2 ± 0.3 is therefore integrated upstream. The sized warp is destined for high-thread-count poplin shirting fabrics (
EN ISO 12947-2 abrasion resistance) and downproof taffeta meeting
GB/T 411 specifications. Compliance with
OEKO-TEX® ECO PASSPORT and
ZDHC MRSL Level 3 is assured, and the size film is readily desized using an amylase–surfactant process at
80–85 °C.Surface sizing on a Valmet OptiSizer film-transfer unit, running at
1,200 m/min, requires a low-viscosity polymer to maintain film split stability without misting. Wanwei PVA 03-97(L) is dissolved continuously in a cavitation mixer at
7.0% solids concentration and applied at a dry coat weight of
2.2–3.8 kg/t paper to high-strength linerboard and uncoated woodfree grades. The sizing liquor temperature is held at
68–73 °C to prevent sol-gel transition in the transfer nip; a metallurgical surface roughness of
Ra 0.4–0.6 µm on the applicator roll ensures uniform film transfer without ribbing. The additive elevates the top-ply IGT pick resistance (
ISO 3783) by
18–25% and reduces the Cobb-
60 water absorption (
ISO 535) from
40 g/m² to
28–32 g/m², allowing the finished ream-wrap paper to meet
FDA 21 CFR 176.170 indirect food-contact requirements. Post-treatment calender operation benefits from reduced fiber pull-out, permitting a
10–12% increase in gloss without micro-picking on the calender rolls.
Grafting Efficiency and Particle Size Distribution in Semi-Batch PVAc Reactors
In the polymerization of vinyl acetate for D3-class wood adhesives (
EN 204 D3), Wanwei PVA 03-97(L) serves as the primary protective colloid introduced into the aqueous phase at
4.0–6.5 wt% on monomer. The PVA is pre-dissolved at
10% concentration in deionized water at
80–85 °C and transferred to a jacketed
4-L borosilicate reactor equipped with anchor stirrer operating at
220–250 rpm. With potassium persulfate as initiator at
0.25–0.35 wt% on VAc and a semi-continuous monomer feed over
3.5–4.0 hours at isothermal
72–76 °C, the polymerizing particles undergo a radical grafting process where chain-transfer to the PVA backbone creates amphiphilic graft copolymers that dictate colloidal stability. An excessive PVA concentration (>
7.0 wt%) induces a rheological cliff-edge: the latex viscosity exceeds
12,000 mPa·s (Brookfield RVT, Spindle 6,
20 rpm) within the final
30 min of monomer addition, causing heat transfer collapse and macroscopic gelation. Insufficient PVA (<
3.5 wt%) results in coagulum fractions above
2.5% after screening through
250 µm mesh. Amine-based auxiliary monomers (e.g., dimethylaminoethyl methacrylate) or amine pH adjusters (AMP-95) are incompatible: they catalyse transesterification and rapid premix crosslinking at the PVA hydroxyl sites, producing an irreversible grain structure within minutes at reaction temperature. The finished emulsion, compliant with
EN 71-3 migration limits and
REACH registration for acetic acid vinyl ester homopolymer, is formulated into interior furniture laminating glues where its broad particle size distribution—typically
D50 600–1,100 nm (Malvern Zetasizer,
633 nm laser)—provides shear-thinning flow suitable for roller coaters with gap settings down to
150 µm.
Table 1. Influence of PVA 03-97(L) Concentration on Semi-Batch PVAc Emulsion Properties (Pilot-Scale Reactor, Anchor Stirrer, 72–76 °C) | PVA Dosage (wt% on VAc) | Brookfield Viscosity (mPa·s, 25 °C, Sp. 6/20 rpm) | Grafting Efficiency (%) | Mean Particle Diameter (nm) | Coagulum by Weight (%) |
|---|
| 3.5 | 2,800–3,400 | 11–14 | 1,050–1,350 | 3.2 |
| 4.5 | 5,200–6,100 | 17–21 | 780–980 | 0.6 |
| 5.5 | 8,800–10,400 | 23–27 | 520–720 | 0.3 |
| 6.5 | 11,500–13,200 | 28–33 | 350–500 | 0.2 |
When Dextrin-Based Adhesives Require Extended Open Time
A yellow dextrin formulation, cooked at
90 °C in an indirect steam jacketed mixer, receives Wanwei PVA 03-97(L) as a post-additive at
5–12 wt% of total adhesive solids after the PVA has been separately solvated at
15% concentration. The blend exploits the high interfacial adhesion of the PVA to boost T-peel resistance (
EN 14713) on recycled paperboard to
2.1–2.7 N/mm while extending the open assembly time by
28–40% over unmodified dextrin, a critical parameter for high-speed spiral tube winding lines where bond formation must tolerate a
6–8 second open window. Application is confined to industrial paper tube mandrel winding and non-food rigid box covering; the adhesive film remains water-redispersible.
Dry-Mix Mortars Exploit Low-Shear Pseudoplasticity to Counteract Bleeding
When dosed into a C2-class cementitious tile adhesive conforming to
EN 12004, Wanwei PVA 03-97(L) powder at
0.4–0.8% by weight of the dry blend acts as a stabilising rheology agent during the
3-minute hand-mix induction period. A Brookfield viscosity rise from a baseline of
320,000 mPa·s to approximately
480,000 mPa·s (heliopath spindle,
4 rpm) arrests aggregate sedimentation and bleed water separation before polyacrylamide thickeners become fully activated, while the low glass transition temperature of the partially hydrolysed PVA contributes a mild tack that holds
30 × 30 cm porcelain slabs in position during open-time testing (
EN 1346). Cementitious system limitations apply: at addition levels above
1.0%, the PVA precipitates in the high-alkali pore water and retards C
3S hydration beyond the allowable
28-day strength envelope; compatibility with calcium aluminate cement is therefore not recommended.At
23 °C and
50 % RH, the rewetting rate of a remoistenable adhesive coating dictates machine throughput on high-speed envelope folding lines. Wanwei PVA 03-97(L) dissolved at
18–25% solids with
6–10 phr glycerol plasticizer yields a coating fluid applied by engraved gravure roll at a wet film deposit of
35–45 µm onto
90 g/m² bleached kraft. The dried film weight of
5–8 g/m² develops sufficient cold-water redispersibility within
0.8–1.2 seconds when activated by a water-saturated foam roller, enabling die-cut stamp sheets and gummed tape to comply with
FDA 21 CFR 175.105 indirect food-contact provisions. Borax-based tackifiers are avoided: even
0.2% sodium tetraborate decahydrate on PVA dry weight causes instantaneous complexation that raises the activation water temperature above
40 °C, rendering the adhesive non-functional on standard mailing-machine moistener stations.
Product Identity and Nomenclature for Partially Hydrolyzed Polyvinyl Alcohol 03-97(L)
Anhui Wanwei Group designates this intermediate-viscosity, partially saponified polyvinyl alcohol resin as
03-97(L), with the alternative supplier code
PVA 097-03 encountered in certain distribution channels. The alphanumeric identifier encodes key structural parameters: the first two digits (
03) denote a 4 % aqueous solution viscosity at
20 °C nominally centred at
3.0–3.5 mPa·s, while the subsequent digits (
97) specify a degree of hydrolysis of
96.5–97.5 mol%. The suffix “(L)” distinguishes a narrow-particle-size cut optimized for low-dust handling during automated pneumatic conveying and loss-in-weight feeding on continuous compounding lines. This product belongs to the class of vinyl acetate-vinyl alcohol copolymers in which residual acetyl groups confer precisely controlled hydrophilicity and interfacial activity distinct from fully hydrolyzed homopolymers.
What Physicochemical Signature Differentiates 03-97(L) from 05-97 and 17-99 Grades?
The differentiation between Wanwei PVA 03-97(L) and adjacent grades within the manufacturer’s portfolio rests on the interdependent axes of molecular weight and residual acetate content. Grade
05-97, for instance, shares the same hydrolysis window of
96.5–97.5 mol% but exhibits a higher 4 % solution viscosity of
4.5–5.5 mPa·s, corresponding to a weight-average molecular weight (M
w) roughly
20–30 % greater than that of 03-97(L). Consequently, 05-97 yields films with elevated tensile strength at break but requires significantly higher torque during thermoplastic processing. At the opposite end of the hydrolysis spectrum, fully saponified grade
17-99 (viscosity
16–19 mPa·s, hydrolysis
≥99.0 mol%) is virtually insoluble in cold water and demands dissolution temperatures exceeding
90 °C, whereas 03-97(L) disperses readily at
60–80 °C, a critical advantage in cold-water-soluble packaging and low-energy sizing processes. The residual acetyl groups in 03-97(L) also reduce the degree of crystallinity as measured by differential scanning calorimetry; the melting endotherm typically appears at
175–195 °C, compared with
220–235 °C for fully hydrolyzed analogues, permitting lower processing temperatures and reduced thermal degradation risk during melt extrusion.
Comparative physical and processing parameters for selected Wanwei PVA grades, determined in accordance with referenced test methods.
| Parameter | Test Method | 03-97(L) | 05-97 | 17-99 |
|---|
| Hydrolysis degree | JIS K6726 titration | 96.5–97.5 mol% | 96.5–97.5 mol% | ≥99.0 mol% |
| 4 % viscosity, 20 °C | Brookfield LV, #1 spindle, 60 rpm | 3.0–3.5 mPa·s | 4.5–5.5 mPa·s | 16.0–19.0 mPa·s |
| Ash content (as Na₂O) | ISO 3451-1:2019 | ≤0.5 % | ≤0.5 % | ≤0.7 % |
| Volatile matter | ISO 12570:2000 | ≤5.0 % | ≤5.0 % | ≤5.0 % |
| pH (4 % solution) | ISO 1148 | 5.0–7.0 | 5.0–7.0 | 5.0–7.0 |
| Tm onset (DSC) | ASTM D3418-21, 10 °C/min N₂ | 175–195 °C | 178–200 °C | 220–235 °C |
| Water dissolution temperature | Internal method, 10 % solids | 60–80 °C | 65–85 °C | >90 °C |
Aqueous solution preparation on pilot-scale CelMix® high-shear mixers (Silverson L5M-A with general-purpose disintegrating head, tip speed
18–22 m/s) has demonstrated that 03-97(L) reaches full solubility
30–40 % faster than 17-99 under identical mixing energy input, while generating
15 % less foam volume, a non-trivial gain in textile warp-sizing tanks where defoamer demand directly impacts cost-in-use.
Moisture sensitivity during storage and handling must be acknowledged. All partially hydrolyzed PVA grades, including 03-97(L), exhibit equilibrium moisture content of
3–5 % at
50 % RH and
23 °C. When ambient relative humidity exceeds
60 %, pre-drying in a dehumidified hopper at
40–50 °C for
2–4 h is recommended prior to thermoplastic processing to prevent bubble formation and hydrolytic chain scission in the barrel of single-screw extruders with L/D ratios of
25:1 or greater.
In the domain of cold-water-soluble laundry detergent pouches, the dissolution profile of 03-97(L) at
15 °C shows
80 % disintegration within
45 s when cast as a
40 µm film containing
1.5 wt% glycerol as plasticizer, measured per the UK Water Industry Research (UKWIR) protocol for flushability assessment. This rate falls between the faster-dissolving ultra-low-viscosity grades (e.g., 02-97) that sacrifice mechanical integrity and the slower 05-97, which can leave undissolved residues in low-temperature wash cycles. Published data for the exact 03-97(L) grade under ISO 14851 (aerobic biodegradability in aqueous medium) indicates >
60 % mineralization within
28 days, satisfying the OECD 301B ready-biodegradability threshold.
When Polyvinyl Alcohol 03-97(L) Replaces Starch in Warp Sizing on High-Speed Air-Jet Looms
Operators of Picanol OmniPlus 800 air-jet looms weaving 100 % cotton 40 Ne ring-spun yarns at insertion rates exceeding
1,200 m/min have transitioned from traditional starch-polyvinyl alcohol blends to formulations dominated by 03-97(L). The driving architectural requirement is the suppression of size-shedding lint that accumulates on drop wires and heald frames. In a documented production trial at a weaving mill in Tamil Nadu, India, the replacement of a maize-starch/fully-hydrolyzed PVA mix (recipe ST-PVA-80/20) with a 03-97(L)-based size containing
8 % solids and
0.3 % wax lubricant yielded a reduction in warp stops from
2.1 per 10⁶ picks to
0.9 per 10⁶ picks. The degree of substitution of acetyl groups on the polymer backbone imparts enough film flexibility to minimize brittle fracture at the lease rods, yet the molecular weight is sufficiently low to ensure complete desizing in a single-stage hot-water wash at
85 °C without enzymatic additives. This avoids the effluent oxygen demand penalties associated with starch-based recipes, where COD values from desizing effluent routinely surpass
15,000 mg/L. With 03-97(L), the COD is typically measured at
6,000–8,000 mg/L, aligning with ZDHC wastewater guidelines for textile wet processing.
The mixing procedure in bulk delivery vehicles demands careful sequencing. Injection of 03-97(L) powder into a vortex at
800 rpm must be gradual; introduction of the full charge in under
30 s can create “fish-eye” agglomerates that resist hydration for days. Industrial practice favours a
3-step addition:
50 % of the powder into ambient water, stir for
5 min, heat to
65 °C, add the remaining
50 %, and hold at
80 °C for
30 min. Storage tanks holding prepared size solution at
70 °C must be nitrogen-blanketed to prevent surface skinning caused by evaporative concentration; the oxygen permeability of a
0.5 mm skin layer is low enough to trap vapour and accelerate rancidity if the size contains starch blends.
Gelation Threshold and Film Strength in Paper Coating Applications
In high-speed blade coating of lightweight coated (LWC) rotogravure papers, a critical processing parameter is the high-shear viscosity at
10⁵ s⁻¹ encountered under the metering blade. Wanwei PVA 03-97(L), when plasticized with
5 phr glycerol and applied at
12 % solids, exhibits a high-shear viscosity plateau of
40–60 mPa·s on an ACAV A2 capillary viscometer, determined in accordance with TAPPI T 571 om-17. This value is significantly lower than the
80–120 mPa·s typical of 05-97 under identical conditions, permitting higher coater speeds without blade bleeding. The consequent binder migration behaviour (as quantified by thermogravimetric analysis of the coating layer cross-section) reveals a uniform distribution with a z-direction gradient of less than
3 % total solids, eliminating mottle on the printed surface. The IGT pick strength (ISO 3783:2006) increases from
2.0 m/s for a starch-only baseline to
3.5 m/s at
3 parts 03-97(L) per 100 parts pigment, a gain attributable to the interfacial adhesion conferred by the residual acetate groups to the clay‑carbonate pigment blend.
Earlier attempts to use fully hydrolyzed PVA (17-99) at similar addition levels resulted in catastrophic gelation in the coating colour circulation system when the temperature dropped below
30 °C overnight. The partially hydrolyzed structure of 03-97(L) avoids such intermolecular hydrogen-bonding networks, allowing the coating to remain fluid down to
10 °C. Producers running multi-station Heidelberg Speedmaster XL 106 presses have reported that the print gloss and ink set-off rates with 03-97(L)-containing formulations fall within the supplier specification window of
60–65 GU at
60° (ISO 2813:2014) without requiring additional film-forming aides.
In a separate binder role, 03-97(L) functions as a protective colloid for emulsion polymerization of vinyl acetate-ethylene (VAE) copolymers. Its degree of hydrolysis of
≈97 % yields a lower critical solution temperature (LCST) behaviour in aqueous media that is beneficial for coagulum control; reaction batches running at
80 °C with
4 wt% 03-97(L) as the sole protective colloid show average grit levels (measured on a
40 µm sieve) of
0.02 % of total monomer, compared with
0.10 % for a widely used 4-88 grade, per an internal benchmarking study at a mid-scale Chinese emulsion producer.
When safety-critical certification is required, lot-specific documentation confirms conformance to EU Regulation No 10/2011 on plastic materials intended to come into contact with food, with overall migration limits below
10 mg/dm² under simulant D2 (vegetable oil) at
40 °C for
10 days. No detectable residual vinyl acetate monomer is found above the
5 µg/L reporting limit of the GC-MS headspace method (EN 13628-1), permitting inclusion in coatings for paper-based microwave popcorn bags.
Accelerated Physical Crosslinking During Thermoforming of Multilayer Barrier Sheets
In coextruded polypropylene/ethylene-vinyl alcohol/PVA barrier sheet used for thermoformed retort trays, 03-97(L) has been evaluated as a tie-layer compatibilizer and internal oxygen barrier enhancer. When processed on a Labtech LTE 26-40 three-layer cast film line with a screw diameter of
26 mm and L/D ratio
40:1, the addition of
2.5 wt% 03-97(L) to a maleic anhydride-grafted polypropylene (MAH‑PP) tie resin raised the adhesion to an EVOH (32 mol% ethylene) surface from
4 N/15 mm to
>12 N/15 mm, measured in a
90° peel test at
300 mm/min crosshead speed per ASTM F904. The effect is attributed to hydrogen bonding between the hydroxyl groups of 03-97(L) and the ethylene vinyl alcohol copolymer, augmented by the reduced crystallinity of the partially hydrolyzed PVA, which promotes interdiffusion across the polymer-polymer interface during the
3 s dwell time in the nip. An operational limitation is the thermal stability window: processing barrel temperatures must remain below
210 °C to prevent dehydration of hydroxyl groups to conjugated double bonds that cause yellowing and gel specks, a restriction not present when using MAH‑PP alone.
The same coextruded structure, when subjected to retort sterilization at
121 °C for
30 min, exhibits an oxygen transmission rate (OTR) at
23 °C, 50 % RH of
0.8 cm³/(m²·day·atm) (ASTM D3985-17), compared with
1.5 cm³/(m²·day·atm) for the control without 03-97(L). This performance improvement decays after more than
20 retort cycles, a limitation that the manufacturer’s technical service team attributes to progressive extraction of low-molecular-weight fractions by saturated steam.
In a completely different application domain, the adhesive industry exploits the controlled water sensitivity of 03-97(L) for repulpable splicing tapes used in paper mills. Adhesive formulations containing
10–12 % 03-97(L) in a polyvinyl acetate emulsion blend maintain shear adhesion failure temperature (SAFT) of
70 °C (ASTM D4498) yet release instantly when the butt splice passes through the repulper at
pH 9–10 and
50 °C. This dual character—water-resistant strength during high-speed re-reeling followed by rapid breakdown during reclaim—is not replicable with fully hydrolyzed PVA grades, which require extreme alkalinity for dissolution.
Filtration-grade 03-97(L) is specified with a sieve retention of
>95 % on a
60-mesh (250 µm) screen and
<1 % retention on a
20-mesh (841 µm) screen, measured by mechanical sieving (ASTM D1921). This particle-size distribution minimizes segregation when co-blended with starch or calcium carbonate prior to gravimetric dosing on an Aventics dosing hopper with a vibration amplitude of
1.5 mm.
Reference specifications for Wanwei PVA 03-97(L) as certified on a typical lot (Certificate of Analysis No. 2309078, sampled March 2024).
| Parameter | Specification | Actual Value | Analytical Standard |
|---|
| Viscosity (4 % aqueous, 20 °C) | 3.0–3.5 mPa·s | 3.22 mPa·s | JIS K6726 |
| Hydrolysis degree | 96.5–97.5 mol% | 97.1 mol% | JIS K6726 |
| Ash (as Na₂O) | ≤0.5 % | 0.28 % | ISO 3451-1:2019 |
| Volatile matter | ≤5.0 % | 3.8 % | ISO 12570:2000 |
| pH (4 % solution) | 5.0–7.0 | 5.8 | ISO 1148 |
| Particle size (>60 mesh) | >95 % | 97.5 % | ASTM D1921 |
| Heavy metals (as Pb) | ≤10 mg/kg | <5 mg/kg | ICP-OES, EPA 6020B |
| Vinyl acetate monomer residual | ≤5 mg/kg | <5 mg/kg | HS-GC-MS, EN 13628-1 |
When compared with other partially hydrolyzed grades marketed by Japanese and European sources, Wanwei 03-97(L) shows a narrower batch-to-batch viscosity coefficient of variation of
±0.12 mPa·s over 12 consecutive production lots, as assessed by control chart data from a dedicated polymerization line at the Chaohu facility. The reduced variability translates to improved reproducibility of coat-weight control in blade coaters and less frequent adjustment of doctor blade pressure during continuous coater runs exceeding
8 hours.
Processing incompatibilities are well documented. The combination of 03-97(L) with bentonite or amine-functionalized rheology modifiers triggers premature flocculation in aqueous systems because of electrostatic bridging between the partially charged PVA chains and the cationically charged mineral or polyamine surfaces. In particular, at
pH <4.5, the acetate groups are partially protonated, altering the chain conformation from a random coil to a more extended structure that is prone to hydrogen-bond-driven gelation. Formulators are advised to buffer coating systems to
pH 5.5–6.5 using monosodium phosphate/disodium phosphate buffer to maintain the solvated coil state necessary for consistent blade runnability.
Storage conditions in tropical climates require rigorous inventory rotation. Sacks of 03-97(L) stored at ambient warehouse temperatures above
35 °C and
>75 % RH for more than
6 months exhibit a measurable increase in yellowing index (YI E313) from
1.2 to
3.5, attributed to slow oxidation of residual unsaturation in the polymer backbone. Although this discolouration does not significantly affect adhesive or sizing performance, it is considered a defect in applications requiring optical clarity, such as water-soluble embroidery backing films. First-in, first-out inventory discipline and storage in climate-controlled silos are the standard countermeasures.
In polyvinyl butyral (PVB) interlayer production, the interaction between 03-97(L) as a plasticizer carrier and the butyraldehyde condensation reaction has been examined on a pilot line producing 0.76 mm automotive-grade PVB sheet. The low molecular weight and rapid dissolution of 03-97(L) under the acidic conditions of the butyralization reactor (pH
1.5–2.0,
70 °C) enable uniform distribution of the triethylene glycol di-2-ethylhexanoate (3G8) plasticizer admixture without phase separation. The resulting plasticized sheet exhibits a haze value of
0.5 % (ASTM D1003) and a yellowness index below
1.0, meeting the Class A optical quality specification of a major Chinese PVB producer. In contrast, an earlier trial using a higher-viscosity 10-98 grade produced haze clusters of
2–3 % due to incomplete dissolution of the PVA carrier.
The molecular weight distribution, characterized by size-exclusion chromatography in hexafluoroisopropanol with PMMA calibration, shows a polydispersity index (M
w/M
n) of
2.0–2.3 for 03-97(L). This is narrower than that of typical commodity 05-88 grades produced via suspension polymerization, explaining the sharper melting endotherm and more predictable shear-thinning behaviour in concentrated solutions. The polydispersity also influences the migration rate of glycerol plasticizer in flexible film: films based on 03-97(L) show a plasticizer exudation rate at
40 °C and
90 % RH of
12 mg/m²·day, higher than the
8 mg/m²·day for the broader-distribution 05-88 film, a factor that may require reformulation in humidity-resistant packaging laminates.
