Page 27 - Engineered Interfaces in Fiber Reinforced Composites

10 Engineered interfaces in fiber reinforced composites

Table 2.1 (contd.)
Liquids YSV (mJ/m2) YLV @Jim2) Referencesa
Polyester 40.4 1
DER 330 epoxy 39.33 1
Polypropylene (PP) 29.8 2
Nylon 6,6 polyamide (PA) 46.5 2
Polyethylene terephtalate (PET) 44.6 2
Polymethyl methacrylate (PMMA) 41.1 2
Polystyrene (PS) 40.7 -2 ~ ..-
High density polyethylene (HDPE) 35.7 2
Polycarbonate (PC, Lexan 101) 33.5 2
Polysulfone (PSU, Udel P-1700) 30.71 2
NPDGE epoxy 36.33 4
HMDS silicone oil 16.33 4
Glycerol 63.4 5
Formamide 58.2 5
Water 72.6 5
Methylene iodide 48.6 5
1 -bromonaphthalene 44.6 5
Polyglyd E-200 43.5 5
Dimethyle sulfoxide 43.3 5
Iodoethanol 44.9 5
"Ref 1: Gutowski, 1988. LM = low modulus
Ref 2: Gutowski, 1990. IM = intermediate modulus
Ref 3: Gilbert et al., 1990. HM = high modulus
Ref 4: Lee et al., 1988. UD = unidirectional
Ref 5: Kinloch et a]., 1992. NPDGE = Neopentyl diglycidyl ether
HMDS = Hexamethyl disiloxane

wets the wall of the capillary, the liquid surface is thereby constrained to lie parallel
with the wall, and the complete surface must be concave in shape, as shown in
Fig. 2.3. The driving force for infiltration, AP, is a direct function of the surface
tension of the liquid, yLv, and inversely related to the effective radius of the
capillary, r,
2yLV COS e
AP = Apgh = 7
rC
where Ap is the difference in density between the liquid and gas phases, g the
acceleration due to gravity, and h the height of the meniscus above the flat liquid
surface for which AP must be zero. Again it is clear that the contact angle is one of
the most important parameters controlling the capillary forces that are present only
when 9 < 90".
The surface free energies of the separate phases may also be considered in terms of
distinctive additive components

y = yd + YP