tensile test

Tensile performance is one of the most important and fundamental mechanical properties of polymers. The quality of tensile performance can be verified through tensile testing. The data provided through tensile testing can evaluate the tensile properties of polymer materials, providing reference for product quality assessment, product acceptance, and the design and development of new materials.

tensile testIt refers to the constant speed stretching along the longitudinal axis of the specimen under specified test conditions until the specimen fractures or the stress (load) or strain (elongation) reaches a predetermined value, and the load and elongation borne by the specimen during this process are measured. Among them, sample preparation and appearance inspection are carried out according toGB1039Regulations are in place. Measure the stress of the specimen during the tensile deformation process-Strain curve, graph1For typical stress-Strain curve. stress-The strain curve is generally divided into two parts: the elastic deformation zone and the plastic deformation zone. In the elastic deformation region, the material undergoes fully recoverable elastic deformation, and the stress and strain are linearly related, in accordance with Hooke's law. In the plastic deformation zone, deformation is irreversible plastic deformation, and the increase in stress and strain is no longer proportional. From stress-On the strain curve, various tensile performance indicators of the material can be obtained, including tensile strength, fracture strength, elongation at break, tensile fracture stress, tensile yield stress, tensile modulus of elasticity, Poisson's ratio, etc. Among them, tensile strength, also known as tensile strength, reflects the ability of a material to resist tensile failure.

Different polymer materials and measurement conditions exhibit different stresses-Adaptive behavior. According to stress-The shape of the strain curve can be roughly classified into five types:

（1）Soft and weak. Low tensile strength, small elastic modulus and small elongation, such as swollen gel.

（2）Hard and brittle. High tensile strength and elastic modulus, low elongation at break, such as polystyrene.

（3）Hard and strong. High tensile strength and elastic modulus, with appropriate elongation, such as rigid polyvinyl chloride.

（4）Soft and resilient. High elongation at break and tensile strength, but low modulus of elasticity, such as natural rubber, butadiene rubber, etc.

（5）Hard and tough. High elastic modulus, tensile strength, and elongation at break, such as polyethylene terephthalate, nylon, etc.