UV protection in Composite material

Fiber Reinforced Polymers (FRP) are unique composite materials in many respects. They can be formulated to be corrosion, abrasion, and UV resistant, as well as smoke and fire retardant.

Accelerated Outdoor Weathering Test (ASTM G90) indicates that the degradation of resin caused by UV light which is the primary reason for the loss of bond between concrete and FRP. This results in fiber blooming which is an undesirable condition where the polymer matrix undergoes UV degradation, exposing the glass fibers underneath. Effects of fiber blooming include Poor aesthetics, degraded mechanical properties and shortened service life for fiberglass sections.

To protect the effect of UV degradation, UVA (ultraviolet absorbers) additives need to be added while manufacturing the FRP structures. Also Fiberglass with a UV protective 2 part painting has much better UV stability to prevent UV-induced polymer degradations when exposed to sunlight and therefore have a longer service life than those without any coating.

Why UV Protection is a must for Pultruded fiber sections?

Degradation of Fiber Reinforced Polymer (FRP) composite due to exposure to ultraviolet (UV) radiation is an important challenge as it reduces the quality and function of FRP thereby impacting its tensile strength and load carrying capacity.

It also leads to polymer disassociation and micro-cracking which invites an implicit loss to durability and safety of the composite. Moreover, extreme environments can severely damage the mechanical and structural integrity, thereby making UV protection essential for pultruded fiber sections and that is only why it is highly recommended.

Scientific Impact of UV radiation on FRP

  • Fiber Blooming – A chemical attack on the fiber in the matrix that leads to the deterioration. It makes the free fibers come out of the FRP material and can cause skin infection when touched.
  • Discoloration – The intensity of the UV radiation and aggressive environments can lead to the discoloration of the FRP structure leading to less stable coloring pigment thereby influences the quality of the material.
  • Chalking – A chalking effect appears on the upper material making the UV radiations penetrate more into the fiber section thereby causing in-depth damage.

How UV protection can be done?

  • Using Pigmentation – As standard resins are more or less transparent so color pigments can be used to prevent the penetration of UV radiation.
  • High quality Additives – Numerous UV inhibitors, anti-oxidants, UV absorbers and UV light stabilizers can be used.
  • Safe Synthetic outer veil – This veil prevents the penetration of fibres to the outside as it is processed during the pultrusion process for various constructions to avoid damage of the human which happens due to the fiber blooming.
  • Resin rich protective layer – Since UV degradation is a surface phenomenon, so a resin rich protective layer is placed between the structural fiber and the outer surface so that the integrity of the reinforcement can be ensured. As a matter of fact, the thicker the coating will be, there will be better surface weathering toleration.
  • Doing Painting – The fiber section can be painted with high quality polyurethane paint so that neither blooming nor degradation occurs.

Special UV cure for pultruded fiber sections at SGS Frangible

Since, SGS Frangible offers high quality composite products and structures; it ensures UV protection by taking care of standard processes in the steps involved. In this respect, usage of special and exclusive resins and additives are done along with stable and environment friendly pigmentation that offers the true sense of UV protection. It also makes the pultruded fiber sections hold the mechanical and structural properties for achieving durability, good tensile strength and load capacity. Moreover, plasticization, cracking, polymer disassociation and degradation are prevented in the most desired manner and thus lead to high performance and safety of the structures.

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