Mechanical properties of the encapsulant material for photovoltaics

Creep lifetime of ethylene vinyl acetate co-polymer film after pre-load relaxation

“…Its magnitude derived from the experimental macroscopic data correlates with the bond energy but tends to be lower than the actual value for the covalent bond. This result is close to that gained earlier by other researchers [10,29].…”

“…11) are estimated to be 13 mol.% and 7.4 nm, correspondently. The value of 𝜉 𝑐 revealed from the XRD data agrees well with the value calculated on the basis of the 720 -730 nm FTIR spectrum line [10,36].…”

“…The thin crack of the length of 𝑙 = 2𝑎 can be taken as a proper approximation. The preliminary conditions for the crack length estimate envisage the existence of anchoring points [10], i.e. the internal "grips" which transfer the external load to the polymer chains directly.…”

“…The routine described in the "Experimental procedure" section in the paragraph concerning the sample pre-loading stage (Fig. 3) is developed on the basis of the preliminary experiments and their analysis [10]. One of the principal summary of that study was the specific behavior of the loading curve with two distinct regions being revealed and the transition point defined as the intersect of two tangent lines coming through initial and fracture points of the stress-strain dependence in the double logarithmic scale (Fig.…”

“…Such a sequence is expected to produce an aligned polymer state with its creep time (under a constant load) being associated dominantly with the covalent component directly. The value of the preloading should be taken from the range corresponding to the fracture mode [10] marked as the process II (Fig. 2b, top inset).…”