Butyl Rubber typically contains about 98% polyisobutylene with 2% isoprene distributed randomly in the polymer chain. To achieve high molecular weight, the reaction must be controlled at low temperatures (-90 to -100 degC).The reaction is highly exothermic.utyl Rubber typically contains about 98% polyisobutylene with 2% isoprene distributed randomly in the polymer chain. To achieve high molecular weight, the reaction must be controlled at low temperatures (-90 to -100 degC).
There may be no single cause of bipolar disorder (aka manic depression). Instead, research indicates the causes of bipolar disorder are probably a combination of biochemical, genetic and environmental factors that may trigger and perpetuate the chemical imbalances in the brain.
Experts believe bipolar disorder is partly caused by an underlying problem with specific brain circuits and the balance of brain chemicals called neurotransmitters. Three brain chemicals -- noradrenaline (norepinephrine), serotonin, and dopamine -- are involved in both brain and bodily functions.Noradrenaline and serotonin have been consistently linked to psychiatric mood disorders such as depression and bipolar disorder.Dopamine is commonly linked with the pleasure system of the brain.he researchers found that 40% of the 47 first-degree relatives of the bipolar II patients also had bipolar II disorder; 22% of the 219 first-degree relatives of the bipolar I patients had bipolar II disorder. However, among patients with bipolar II, researchers found only one relative with bipolar I disorder.