The long-term natural aging of isotactic polybutene-1 samples of different molecular weight has shown that the transformation rate from the initial phase II to the stable phase I significantly decreased after natural aging, ranging from 0 to 17 years. It was found that the total crystallinity decreased with aging time and a small amount of phase II remained untransformed for at least 17 years. The transformation rate of a lower molecular weight sample, DP 0400, was higher than the PB 0110 sample, even after repeated polymer melting of aged samples and their new melt crystallization. The major phenomenon of the iPB-1 aging is the change in a ratio of methyl/methylene functional groups; possibly because of a side chain splitting that reduces the geometric regularity of the molecular chain and consecutively slows down the proceeding phase transformation.

不同分子量的等规聚丁烯-1样品的长期自然老化表明，自然老化后，从初始相II到稳定相I的转化率明显降低，范围为0至17年。发现总的结晶度随老化时间而降低，并且少量的第二相保持至少17年未转化。较低分子量的样品DP 0400的转化率高于PB 0110样品，即使在老化的样品反复进行聚合物熔融并重新结晶后，其转化率也更高。iPB-1老化的主要现象是甲基/亚甲基官能团比例的变化。