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Preparation and corrosion resistance analysis of composite polyurethane wind turbine blade materials

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Jun 27, 2025

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Figure 1

Sample preparation process.
Sample preparation process.

Figure 2

The influence of different NCOs on the mechanical properties of materials: (a) tensile strength and hardness and (b) tensile elongation at break.
The influence of different NCOs on the mechanical properties of materials: (a) tensile strength and hardness and (b) tensile elongation at break.

Figure 3

The influence of different PCL molecular weights on the mechanical properties of materials: (a) tensile strength and hardness and (b) tensile elongation and tensile stress at break.
The influence of different PCL molecular weights on the mechanical properties of materials: (a) tensile strength and hardness and (b) tensile elongation and tensile stress at break.

Figure 4

SEM images of titanium dioxide with different contents: (a) 3%, (b) 6%, (c) 9%, and (d) 12%.
SEM images of titanium dioxide with different contents: (a) 3%, (b) 6%, (c) 9%, and (d) 12%.

Figure 5

Trend of rainfall in rain erosion experiment.
Trend of rainfall in rain erosion experiment.

Figure 6

HO-PDMS infrared spectrum and HO-PDMS content spectrum with different molecular weights: (a) infrared spectrum of HO-PDMS and (b) infrared spectra of different HO-PDMS contents.
HO-PDMS infrared spectrum and HO-PDMS content spectrum with different molecular weights: (a) infrared spectrum of HO-PDMS and (b) infrared spectra of different HO-PDMS contents.

Figure 7

Microscopic images under different HO-PDMS contents: (a) SiPU-500, (b) SiPU-1000, and (c) SiPU-2000.
Microscopic images under different HO-PDMS contents: (a) SiPU-500, (b) SiPU-1000, and (c) SiPU-2000.

Figure 8

The influence of different molecular weights of HO-PDMS on mechanical properties and contact angle: (a) tensile strength and hardness, (b) tensile elongation at break and contact angle, and (c) dynamic mechanics testing.
The influence of different molecular weights of HO-PDMS on mechanical properties and contact angle: (a) tensile strength and hardness, (b) tensile elongation at break and contact angle, and (c) dynamic mechanics testing.

Figure 9

Effects of different dosages of HO-PDMS on rain erosion and mechanical properties: (a) tensile strength and rain erosion time; and (b) contact angle and elongation at break.
Effects of different dosages of HO-PDMS on rain erosion and mechanical properties: (a) tensile strength and rain erosion time; and (b) contact angle and elongation at break.

Figure 10

TGA of HO-PDMS with different dosages: (a) TGA and (b) DTG.
TGA of HO-PDMS with different dosages: (a) TGA and (b) DTG.

Figure 11

Dynamic mechanical testing of HO-PDMS with different dosages: (a) storage modulus and (b) loss modulus.
Dynamic mechanical testing of HO-PDMS with different dosages: (a) storage modulus and (b) loss modulus.

Comparison of demolding, gel, and constant elongation strength of materials with different NCO contents_

NCO (%) Stripping time (min) Gel time (min) 300% Fixed extension strength (MPa)
4.0 201.2 29.1 10.5
4.5 191.2 28.5 10.6
5.0 190.2 24.9 11.2
5.5 181.2 21.4 11.6
6.0 180.0 20.3 12.2
6.5 179.5 17.1 13.3
7.0 179.5 15.2 15.5
7.5 159.5 13.1 17.6
8.0 155.2 10.3 18.9
8.5 130.0 9.4 19.5
9.0 112.5 8.2 20.1
9.5 112.3 8.2 20.1

Properties of elastomeric materials under different catalyst types and dosages_

Type Without catalyst Cat Hb21
Usage 0.03% 0.05% 0.10% 0.03% 0.05%
Tensile strength (MPa) 15.4 18.2 20.8 24.4 23.4
Hardness (shore a) 81.8 74.4 72.4 73.4 75.9
Tensile elongation at break (%) 260 389 374 378 407
300% tensile stress (MPa) 9.1 11.8 12.0 9.6
Demolding time (min) 199 59 49 41 (Forming Failed) (Forming Failed)
Lifespan in a kettle (min) 36 11 11 7 7
Type 2130 2210
Usage 0.05% 0.10% 0.15% 0.02% 0.03% 0.05%
Tensile strength (MPa) 24.2 18.0 24.5 25.5 27.7
Hardness (shore a) 76.1 73.2 72.2 77.1 77.2
Tensile elongation at break (%) 355 341 354 352 393
300% tensile stress (MPa) 13.3 11.6 12.4 13.1 12.2
Demolding time (min) 58 38 29 89 49 (Forming failed)
Lifespan in a kettle (min) 14 11 8 7 5

Parameter settings for comprehensive environmental experiments_

Experimental parameters Set value Reference standard
UV irradiation UVA-340 lamp, irradiation intensity 0.68 W/m2 @ 340 nm, simulating summer noon sunlight intensity ASTM G154-2006
Salt spray corrosion Neutral salt spray (5% NaCl solution, pH 6.5–7.2, temperature 35°C), spray cycle: 4 h salt spray/4 h drying ISO 9227
Cyclic heat load Temperature cycle: −10°C (nighttime) → 70°C (daytime), temperature rise and fall rate of 5℃/min, simulating the temperature difference between day and night IEC60068-2-14
Long-term exposure simulation Accelerated aging cycle: 1,000 h (equivalent to approximately 1 year of outdoor exposure) ASTM D4329

Comprehensive test results of accelerated aging of materials in composite environment_

Performance index Initial value After accelerated aging (1,000 h) Degradation rate (%) Key factors
Tensile strength (MPa) 28.7 22.1 (±0.5) −23 UV rays cause chain breakage and salt spray penetration
Tensile elongation at break (%) 507 380 (±15) −25 The separation between hard and soft segments intensifies
Shore a hardness 84.8 78.5 (±1.2) −7.40 Surface oxidation and plasticization
Rain erosion lifespan (h) 31.6 18.2 (±0.8) −42 Microcrack propagation acceleration
Contact angle (°) 102 88 (±3) −14 PDMS surface migration is hindered
TGA residual carbon rate (600℃) 19.28% 15.02% (±0.3) −22 Acceleration of Thermal Oxygen Decomposition
Storage modulus (−40℃, MPa) 1,506 1,120 (±45) −26 Low temperature brittleness increases
Surface crack density (pcs/mm2) 0 12.5 (±2.1) Salt crystal expansion stress

Comparison of mechanical and rain corrosion properties of titanium dioxide materials with different contents

Experiment number TiO2 content (%) Tensile strength (MPa) Elongation at break (%) Hardness/shore A Contact angle (°) Rain erosion time (h)
1 0 27.4 392 76.1 85.4 11.5
2 3 29.5 414 77.9 84.6 13.8
3 6 30.5 403 82.6 86.4 15.8
4 9 32.4 425 84.8 85.7 17.5
5 12 25.7 397 87.4 86.7 14.8