Non-ideal balloons[edit]
At large extensions, the pressure inside a natural rubber balloon once again goes up. This is due to a number of physical effects that were ignored in the James/Guth theory: crystallization, imperfect flexibility of the molecular chains, steric hindrances and the like.[5] As a result, if the two balloons are initially very extended, other outcomes of the two-balloon experiment are possible,[1] and this makes the behavior of rubber balloons more complex than, say, interconnected soap bubbles.[4] In addition, natural rubber exhibits hysteresis: the pressure depends not just on the balloon diameter, but also on the manner in which inflation took place and on the initial direction of change. For instance, the pressure during inflation is always greater than the pressure during subsequent deflation at a given radius. One consequence is that equilibrium will generally be obtained with a lesser change in diameter than would have occurred in the ideal case.[1] The system has been modeled by a number of authors,[6][7] for example to produce phase diagrams[8] specifying under what conditions the small balloon can inflate the larger, or the other way round.