The reinforcement and matrix of polypropylene self-reinforced composites (All-PP) are the same polymer polypropylene

and its mechanical properties are extremely sensitive to temperature. Studying the temperature effect of its mechanical properties has important guiding significance for the use of this material and hot stamping. In this paper

the thermal properties of the All-PP were characterized by differential scanning calorimetry (DSC)

and the mechanical properties of All-PP were tested in the range of – 40–120 ℃

the material failure interface was characterized by scanning electron microscope (SEM) under different temperature conditions

and the temperature effect was comprehensively analyzed. The results show that the Tg of All-PP is –11.5 ℃

and the tensile strength shows a trend of first increase and then decrease with the increase of temperature

the maximum tensile strength reaches 118.5 MPa at –20 ℃

the interface debonding occurs below this temperature

leading to the decrease of tensile strength; The elongation at break increases with the increase of temperature; The elastic modulus in the glass state is always remains at about 4.86 GPa

which is hardly affected by temperature

when the temperature rises to –10 ℃

the elastic modulus begins to decrease with the increase of temperature; The flexural modulus decreases with the increase of temperature

and decrease sharply at –10 ℃; The interlaminar shear strength decreases linearly in the temperature range of 20 –120 ℃

but is not greatly affected by temperature in the low temperature environment (–40 –0 ℃); The microstructure shows that the shear failure mode changes from interface debonding to matrix failure with the increase of temperature.