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Nano Resins

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Nano Resins

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Page 1: Nano Resins
Page 2: Nano Resins

Product Portfolio for Fiber Composite Applications Depending on the application and desired modification, different products can be used for improving laminating and injection resins:

1. Toughening epoxy resins with copolymers (Albipox®)- Improved impact resistance over a wide temperature range (easier finishing) - Damage-tolerant systems - Improved inter-laminar shear strength, better fiber adhesion - Higher pressure resistance (e.g. in pipes), reduced shrinkage

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2. Toughening epoxy resins with core shell materials (Albidur®) - Improved impact resistance over a wide temperature range - Negative coefficient of expansion, significantly reduced shrinkage - Moderate viscosity increase on addition, no loss with modulus and TG

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3. Modifying epoxy resins with nanoparticles (Nanopox® F, Albipox® F) - Significantly improved modulus and flexural strength - Due to low viscosity increase, suitable for injection processes (e.g. RTM) - Lower CTE, reduced shrinkage - Improved surface quality (Class A)

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4. Modification and elastification of phenolic resins with block copolymers (Albiflex®)- Improved impact resistance over a wide temperature range - Damage-tolerant laminates

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5. Toughening unsaturated polyester resins and vinyl ester resins (Albidur®, Hycar® RLP) - Improved impact resistance over a wide temperature range (easier finishing) - Damage-tolerant systems - Increased pressure resistance (e.g. in pipes), reduced shrinkage - Hydrophobic laminates with reduced water absorption

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Portfolio Fiber Composites – Page 21. Toughening epoxy resins with copolymers

- Improved impact resistance over a wide temperature range (easier finishing) - damage-tolerant systems - Improved inter-laminar shear strength, better fiber adhesion - Higher pressure resistance (e.g. in pipes), reduced shrinkage

Product overview Technical data (no specification) Type NBR*)

[wt%] Base resin EEWg/equiv. Dyn. viscosity, 25°C [mPa·s] CharacterizationAlbipox® 1000 40 DGEBA 330 200,000 standard type Albipox® 1005 50 TMP-TGDE 320 65,000 low viscosity; contains diluents Albipox® 3001 15 DGEBA / DGEBF 215 22,000 application-ready resin *) NBR = Acrylnitril-Butadien-Copolymer Exclusively tailored, customer-specific products are also available for special applications. To modify an existing system, part of the epoxy resin is replaced by Albipox® 1000 or Albipox® 1005 (see also application remarks below). If blending is not possible, the ready-to-use Albipox® 3001 can be em-ployed. Improvements to properties Epoxy resins have a substantial disadvantage: Their brittleness. This disadvantage can be more than compensated by an elastomer modification (so-called "toughening" or impact resistance modification). In contrast to an elastification, the elongation at break of the cured modified resin normally remain under 10 %. The toughening of epoxy resins proves to be difficult, however. Thus, for example, the use of flexible hardeners or the addition of non-reactive flexibilizers significantly impairs a number of important proper-ties such as tensile strength and modulus, thermal and chemical resistance as well as thermodimensional stability. These negative effects can be avoided by toughening with copolymers based on reactive elastomers. However, the pure liquid elastomers are only slightly miscible with epoxy resins, if at all. The different Albipox® grades are reaction products between epoxy resins and an elastomeric copolymer. Hereby, an epoxy resin is reacted with an excess amount of the reactive liquid elastomer. After the reac-tion, the elastomer molecules are epoxy functional and will be chemically bonded to the resin matrix dur-ing curing. Albipox® products are miscible with all epoxy resins in any ratio. Albipox® products can be used by epoxy resin formulators like a modular system. There are no limitations in respect to the resins and hardeners that can be used.

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Portfolio Fiber Composites – Page 3Figure 1 shows the effect of such a resin modification on the laminate. As the glass transition temperature of the liquid rubber used lies in the range -40 °C to - 50 °C, the signifi-cantly improved properties are also found at these lower temperatures. An additional advantage is the improved processability of the modified laminates, thereby avoiding splintering on mechanical finishing. The shrinkage is also reduced, as the rubber domains can absorb the internal stresses arising during curing.Figure 1: Improvement in the laminate properties through the use of toughened epoxy resins

How it works During curing, a phase separation of the elastomeric parts occurs regardless the chemical nature of the hardener and the curing temperatures. This results in finely dispersed rubber domains which are ho-mogenously distributed across the resin. As can be seen in Figure 2, the domain size typically is in the range between 0.2 – 4 µm. For the most part, the rubber domains consist of the relatively long molecules of the elastomer used, and are chemically bonded to the matrix via their epoxy groups at the phase boundary. If a force is now ap-plied to the cured resin system, it can be dissipated uniformly in all directions when encountering a rub-ber domain.

Figure 2: Scanning electron microscope images of a rubber-modified epoxy resin If a tear has already occurred, it is prevented from further tearing: The elastomer particles stretch per-pendicular to the direction of tear and are not torn out, as they are bonded chemically to the matrix. Fig-ure 2 shows the finely distributed elastomer particles in the epoxy matrix (see also Figure 3).

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Portfolio Fiber Composites – Page 4

crack bridging

cavitated rubber domains

shear bands

Figure 3: Schematic representation of the rubber domain under stress

Application remarks The correct ratio of rubber to epoxy is crucial for successfully improving an epoxy resin formulation. Normally, optimum results are obtained with 10 – 15 phr rubber (i.e. 10 – 15 parts rubber on 100 parts resin). Hardeners and fillers etc. are not considered. Part of the epoxy resin used in the formulation is replaced by the type of Albipox® selected. The amount of hardener is adjusted to the altered epoxy equivalent weight of the new resin mixture. An adjustment is not required for non-stoichiometric hardeners such as dicyandiamide. Fillers and other recipe components are used as normal. Sample calculation for the epoxy equivalent when using Albipox® 1000:

Originalformulation 10 phr NBR*) 12 phr NBR*) 15 phr NBR*)Bisphenol-A standard resin (EEW 185) 100 85 82 77.5 Albipox® 1000 (EEW 330) - 25 30 37.5 Total mass elements 100 110 112 115EEW 185 206 210 216

*) NBR = nitrile butadiene rubber If the viscosity of the Albipox® selected is too high for the mixing process used, we recommend preheat-ing to 70 – 80 °C.

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Portfolio Fiber Composites – Page 52. Toughening epoxy resins with core shell materials

- Improved impact resistance over a wide temperature range - Negative coefficient of expansion, significantly reduced shrinkage - Moderate viscosity increase on addition, no loss with modulus and TG

Product overview Technical data (no specification) Type Silicone con-tent [wt%] Baseresin EEWg/equiv. Dyn. viscosity, 25°C [mPa·s] CharacterizationAlbidur® EP 2240 40 DGEBA 300 35,000 C-Silicone base Albidur® EP 2240 A 40 DGEBA 300 35,000 A-Silicone base Albidur® EP 2240 and 2240 A differ in the silicone base: The elastomer particles in EP 2240 are based on a condensation curing silicone, while Albidur® EP 2240 A is based on an addition curing mechanism. This results in a different hydrophobicity of the particles which can be utilized to adjust to the polarity of for-mulations. Improvements to properties Besides the low viscosity, further advantages are the high thermal stability (up to 200 °C) as well as ex-cellent electrical properties. UV and ozone stabilities are also significantly improved. In contrast to the Albipox® products, UP und VE resins can also be modified with Albidur®.Albidur® products consist of a reactive resin in which silicone elastomer particles of a defined size (0.1 – 3 µm) are finely distributed. The silicone elastomer particles have an organic shell structure comprising reac-tive groups (Figure 4). The toughening mechanism is the same as in Section 1; however, the rubber do-mains are already preformed and not built during the curing process.

silicone rubbershell reactive group

Figure 4: Schematic representation of an Albidur® particle

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Portfolio Fiber Composites – Page 63. Modifying epoxy resins with nanoparticles

- Significantly improved modulus and flexural strength - Due to low viscosity increase, suitable for injection processes (e.g. RTM) - Lower CTE, reduced shrinkage - Improved surface quality (Class A)

Product overview Technical data (no specification) Type Base resin EEWg/equiv. Dyn. viscosity, 25°C [mPa·s] CharacterizationNanopox® F 400 DGEBA 295 60,000 special for glass, aramide and car-bon fibers ; 40% SiO2 nanoparticles Nanopox® F 440 DGEBA/DGEBF 290 45,000 crystallization-free; 40 % SiO2 nanoparticles Nanopox® F 520 DGEBF 275 20,000 Low viscous; 40 % SiO2 nanoparticles Nanopox® F 630 EEC 220 5,500 cycloaliphatic formulations; 40 % SiO2 nanoparticles Nanopox® F 640 HDDGE 245 200 for systems with reactive diluents; 40 % SiO2 nanoparticles Albipox® F 080 DGEBA/DGEBF 330 70,000 contains NBR*) and nanoparticles Albipox® F 081 DGEBA/DGEBF 260 35,000 contains NBR*) and nanoparticles *) NBR = nitrile butadiene rubber Improvements to properties Modifying resins for fiber composites with about 10 % nanoparticles significantly enhances the mechani-cal properties of composites. Also, with increasing nanoparticle content the shrinkage is considerably reduced which enables a class-A surface to be attained. The CTE is also significantly reduced. Albipox® F 080 or 081: If laminating or injection resins are modified with both copolymers (based on NBR) and nanoparticles, as realized in these two Albipox® types, the fracture toughness can be significantly in-creased compared to a modification with copolymers alone. Damage-tolerant systems, e.g. for ballistic applications (armor), with a superior property profile can be designed using this approach (Fig. 5).

Control (60 J) CTBN/nanoparticles (60 J)Figure 5: CFRC after 60 J impact testing (unmodified / modified with Albipox F 081)

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Portfolio Fiber Composites – Page 7Figure 6 shows the flexural strength of a glass-fiber reinforced composite produced using VRTM (epoxy resin, anhydride-cured, 60 % glass fiber).

Figure 6: Flexural strength of a GFC depending on the nanopar-ticle content

Due to their small size and the absence of any larger aggregates, the nanoparticles can easily penetrate all fiber structures (Fig. 7) without compromising the impregnation by excessive viscosity, thereby ena-bling all the state-of-the-art process technologies like resin infusion, RTM, or resin injection. In addition to significantly improved mechanical properties (modulus, fracture toughness), the thermal expansion, shrinkage and electrical properties can also be improved.

0 20 40 60 80 100particle size [nm]

particle

numb

er dens

ity

15 % Nano

resin

fiber

4 % Nano

resin

fiber

Figure 7: SEM-Pictures of GFRCs with different levels of SiO2-nano-particles (based on Nanopox F 400)

How it works Nanopox® F products are colloidal silica sols in a resin matrix with surface-modified, spherically shaped silica nanoparticles having diameters below 50 nm and an extremely narrow particle size dis-tribution (Fig. 8). Depending on the application, colloidal silica sols are used in corresponding epoxy resins or as ready-for-use products. The spherical silica is distributed agglomerate-free in the resin ma-trix (Fig. 9). This results in a very low viscosity of the dispersion with SiO2 contents of up to 40 wt%.Figure 8: Particle size distribution (Determined by SANS)

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Portfolio Fiber Composites – Page 8The nanoparticles are chemically synthesized from aqueous sodium silicate solution. In this unique process the binding agent is not damaged, in contrast to processes in which powdered fillers are dispersed with dissolvers or other equipment using high shear energy.

Figure 9: TEM – images of a cured Nanopox® sample with SiO2 nanoparticles

4. Modification and elastification of phenolic resins with block copolymers

- Improved impact resistance over a wide temperature range - Damage-tolerant laminates

Product overview Technical data (no specification) Type Silicone content [wt%] Base resin OH-equivalent weight CharacterizationAlbiflex® H 1083 S1 40 phenolic resin 200 65 % solution in methoxypropanol

Improvements to properties Albiflex® H 1083 S1 is a phenolic resin silicone copolymer which is available for the modification of phe-nolic resins. Toughness and impact resistance of phenolic resin composites can be improved using this Albiflex® type.

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Portfolio Fiber Composites – Page 9

5. Toughening unsaturated polyester resins and vinyl ester resins

- Improved impact resistance over a wide temperature range (easier finishing) - damage-tolerant systems - Increased pressure resistance (e.g. in pipes), reduced shrinkage - Hydrophobic laminates with reduced water absorption

Product overview Technical data (no specification) Type Silicone con-tent [wt%] Base resin Properties Dyn. viscosity, 25°C [mPa·s] CharacterizationAlbidur®UP 6140 40 Glycol /o-phthalic acid 20 % styrene 5,000 modifcation of unsatu-rated polyester resins Albidur®VE 3320 20 Bisphenol A- vinyl ester 30 % styrene 2,000 modifcation of vinyl es-ter resins

Improvements to properties Polyester and vinylester resins can be toughened with core shell materials. A further advantage is the reduced absorption of humidity of the modified laminates.

The information contained in this publication is based on our current state of knowledge, but is unbinding and does not represent an assurance of definite properties. They also do not exempt the processor from his own tests in relation to the usability of our products for his special application purposes. The protection rights of third parties must also be observed. February 2006