连续碳纤维增强聚苯硫醚复合材料的3D打印及力学性能优化

采用连续碳纤维增强聚苯硫醚(CCF/PPS)预浸丝材为原料,通过3D打印制备出不同工艺参数条件下的弯曲试样和层间试样。采用扫描电镜、显微CT、差示扫描量热仪、弯曲性能和层间性能等测试方法对3D打印CCF/PPS复合材料的结构和性能进行了研究。结果表明,打印制品相邻打印层之间的界面、相邻打印线条之间的界面、孔隙结构和结晶结构都对打印制品的弯曲性能和层间性能有重要影响。当打印层厚为0.2 mm、沉积空间为0.40 mm~2,并采用后热处理时,打印制品可获得最高为699 MPa的弯曲强度和43.32 MPa的层间剪切强度,在连续纤维增强热塑性复合材料3D打印研究领域处于领先水平。

α/β复合成核剂协同增强煤基均聚聚丙烯力学性能

针对煤基均聚聚丙烯(PP)结晶过程中β晶型成核生长能力较弱、冲击强度较低的问题,利用差示扫描量热仪(DSC)、广角X射线衍射仪(WAXD)和万能材料实验机研究了单独添加a,β和复合添加a/β成核剂对煤基均聚聚丙烯的结晶性能和力学性能的影响。研究表明,单独添加a或β成核剂均会存在一定的性能缺陷。DSC结果表明,a/β复合成核剂中β成核剂的存在会抑制a晶型的生成,β晶熔融峰强度会增加,在降温结晶曲线中也呈现出明显的β晶优先成核现象。WAXD结果表明,复合成核剂可以提高聚丙烯的β晶体的相对含量(K_(β))。a/β复合成核剂的加入有助于同时实现煤基均聚聚丙烯的刚韧平衡,当复合成核剂质量分数为0.15%、a/β比例为1:2时,PP的拉伸强度、断裂伸长率和冲击强度分别提高了15.9%,305.3%和72.5%。

Electrospun antibacterial nanofibers for wound dressings and tissue medicinal fields:A Review

Bacterial infections are a major cause of chronic infections.Thus,antibacterial material is an urgent need in clinics.Antibacterial nanofibers,with expansive surface area,enable efficient incorporation of antibacterial agents.Meanwhile,structure similar to the extracellular matrix can accelerate cell growth.Electrospinning,the most widely used technique to fabricate nanofiber,is often used in many biomedical applications including drug delivery,regenerative medicine,wound healing and so on.Thus,this review provides an overview of all recently published studies on the development of electrospun antibacterial nanofibers in wound dressings and tissue me-dicinal fields.This reviewer begins with a brief introduction of electrospinning process and then discusses electrospun fibers by incorporating various types of antimicrobial agents used as in wound dressings and tissue.Finally,we finish with conclusions and further perspectives on electrospun antibacterial nanofibers as 2D biomedicine materials.