真空镀膜技术显现聚合物发泡材料上汗潜手印的研究

Development of latent fingerprints on Polymer foamed materialby vacuum metal deposition

发泡聚苯乙烯、聚乙烯发泡棉等聚合物发泡材料常常出现在案发现场,可能承载破获案件的重要证据。以聚合物发泡材料为研究客体,本文利用真空镀膜技术探究喷镀金属组合及其用量对手印显现效果的影响、真空镀膜与“502”熏显组合方法显现手印的效果。研究结果表明,真空镀膜技术与“502”熏显组合方法显现发泡聚苯乙烯上手印显现效果较好,整体显现效果要优于单独真空镀膜法的显现效果。而且银锌、铜锌喷镀金属可以替代传统的金锌喷镀金属组合。对于挤塑聚苯乙烯和聚乙烯发泡棉,因材料本身结构特性导致吸水性差,所以上述几种实验方法均无法得到较好的显现效果,在实际案件中可以先采用真空镀膜法显现出客体上的手印位置,在对其上的DNA进行提取和鉴定。本文为公安工作中显现聚合物发泡材料这类疑难客体上的汗潜手印提供一定的借鉴。

Expandable polystyrene,Expanded ployethylene and other Polymer foamed material often appear at the scene of the crime,which may carry the important evidence.Taking Polymer foamed material as the research object,vacuum coating technology is used to explore the influence of the combination of sprayed metal and its dosage on the effect of handprint、development of latent fingerprints by vacuum metal deposition and cyanoacry late fuming.The research results show that for the development of latent fingerprints on Expandable polystyrene by vacuum metal deposition and cyanoacry late fuming is better than that of the single vacuum coating method.Moreover,silver/zinc and copper/zinc sprayed metals can replace the traditional combination of gold/zinc.For the extruded polystyrene and polyethylene foam cotton,due to the poor water absorption caused by the structural characteristics,the above experimental methods can not get a better development effect.In actual cases,the position of the fingerprint on the object is revealed by vacuum coating method,and then the DNA can be extracted and identified.This paper provides some reference for the development of latent fingerprints on the difficult objects such as Polymer foamed material in the public security work.