由于高强聚苯并噁唑(PBO)纤维耐紫外性差,特别是在湿热、光照条件下,高强PBO纤维噁唑环开环导致性能急剧下降,限制其在高端领域的应用。为提升高强PBO纤维耐紫外性能,引入有机紫外吸收剂,来吸收紫外线能量,减少对PBO纤维的损伤。采用对紫外光更敏感的4,4＇-双(2-苯并噁唑基)芪(OB-1)通过原位共混方式改性PBO,经工业化聚合、纺丝工艺验证可行,得到的OB-1/PBO纤维性能与纯PBO纤维相当。最佳OB-1质量分数为0.150%,经窄带300～340nm氘灯处理24h后,OB-1/PBO纤维强度保持率为81.2%,较纯PBO纤维增加2.7个百分点;处理400h后,强度保持率为60.6%,较纯PBO纤维增加20.8个百分点。

High strength polybenzoxazole (PBO) fibers exhibit poor ultraviolet (UV) resistance,particularly under humid,hot,and illuminated conditions.The degradation of PBO fibers,caused by the ring-opening reaction of the oxazole moiety,leads to a dramatic decline in mechanical properties,limiting their applications in high-end fields.This study aimed to enhance the UV resistance of high-strength PBO fibers by incorporating an organic UV absorber,which effectively absorbed UV energy and mitigated fiber damage.Specifically,4,4′-bis(2-benzoxazolyl)stilbene (OB-1),a UV-sensitive compound,was introduced into PBO via in-situ blending.The modified OB-1/PBO fibers were successfully produced through industrial-scale polymerization and spinning processes,demonstrating comparable performance to pristine PBO fibers.The optimal OB-1 loading was determined to be 0.15wt%.After 24 h of exposure to narrow-band deuterium lamp irradiation (300～340 nm),the tensile strength retention rate of OB-1/PBO fibers was 81.2%,which was 2.7 percentage points higher than that of pure PBO fibers.After 400 hours of treatment,the strength retention rate was 60.6%,representing an increase of 20.8 percentage points compared to pure PBO fibers.