摘要:

AbstractTo ensure the growing use of high‐performance composites such as carbon‐fiber‐reinforced plastics (CFRP), the quality properties of these materials must be guaranteed. This goal can be reached through a quality assurance concept which still has to be developed. The individual steps of such a development are indicated. Flaws occuring in fiber‐rein‐forced composites are discussed, taking into consideration the manufacturing process, and the nondestructive and slightly destructive test methods suitable for flaw selected flaws are given as

ISSN:0730-6679    

DOI:10.1002/adv.1985.060050301

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractA video camera tracer technique (T. A. Huang and G. A. Campbell, paper to be presented at ANTEC '85, Washington, D. C.) was used to obtain MD velocity profile and bubble shape above the air ring under industrial film blowing conditions. Subsequently, the velocity profile and bubble shape were utilized to calculate strain and strain rate histories for a fluid element before it solidified. The deformational history of a fluid element was compared between LDPE and LLDPE of similar melt index and density. Also, the study was extended to two groups of LLDPE/LDPE blends: blends rich in LLDPE and blends rich in LDPE. We used a 100‐mil die gap for extruding resins rich in LLDPE to avoid melt fracture. A 30‐mil die gap was used to process blends that were rich in LDPE. Under the same film blowing conditions and frost line height, LDPE exhibits higher peak strain rates than LLDPE and the peak strain rates for LDPE occur closer to the air ring. Moreover, the MD strain of LLDPE continues to increase above the frost line. Conversely, the MD strain profile of LDPE levels off quickly before the frost line. The observed differences in fluid element deformation between LLDPE and LDPE on the blown film line are attributed to the higher melt tension of LDPE. For LLDPE, a 10 wt % LDPE addition causes a significant increase in strain and strain rate at lower positions. Interestingly, a further addition up to 25 wt % LDPE causes little or no further change in deformational history. The increased strain rates associated with an increased strain results in a stabilized LLDPE bubble. For LDPE, only slight differences in strain and strain histories were observed with the addition of LLDPE up to

ISSN:0730-6679    

DOI:10.1002/adv.1985.060050302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

摘要:

AbstractPolypropylene (PP) compositions containing 0–20 vol % of steel fibers (SF) [neat or with 5 wt % of maleated propylene wax (MPP)] were prepared and tested for electrical and thermal conductivities. It was found that, at room temperature, the volume resistivity Ωvfell below 10 ohm cm at SF loading of about 10 vol %. However, as the test temperature increased to 120°C, higher loadings were required to secure the same resistivity, i.e., 12 and 14 vol % of SF for composites without and with MPP, respectively. By contrast with a sharp decrease of Ωv(by 16 orders of magnitude upon addition of a few percent of SF), the increase of thermal conductivity was much less dramatic. The thermal conductivity k of the composites was found to be proportional to volume loading, increasing by a factor of 1.8 on addition of 20 vol % of SF, independently of temperature and MPP presence. Annealing had a small positive effect

ISSN:0730-6679    

DOI:10.1002/adv.1985.060050303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

ISSN:0730-6679    

DOI:10.1002/adv.1985.060050304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY

ISSN:0730-6679    

DOI:10.1002/adv.1985.060050305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1985

数据来源: WILEY