Low-density binderless particleboards from kenaf core were successfully developed using steam injection pressing. The target board density ranged from 0.10 to 0.30 g/cm 3 , the steam pressure used was 1.0 MPa, and the steam treatment times were 7 and 10 min. The mechanical properties, dimensional stability, and thermal and sound insulation performances of the boards were investigated. The results showed that the low-density kenaf binderless particleboards had good mechanical properties and dimensional stability relative to their low board densities. The board of 0.20 g/cm 3 density with a 10-min treatment time produced the following values: modulus of rupture 1.1 MPa, modulus of elasticity 0.3 GPa, internal bond strength 0.10 MPa, thickness swelling in 24 h water immersion 6.6%, and water absorption 355%. The thermal conductivity of the low-density kenaf binderless particleboards showed values similar to those of insulation material (i.e., rock wool), and the sound absorption coefficient was high. In addition, the boards are free from formaldehyde emission. Kenaf core appears to be a potential raw material for low-density binderless panels suitable for sound absorption and thermally resistant interior products.

No abstract

The durability of the dissimilar material joint between a steel coated with a roughened nickel plating‐film and a thermoplastic resin is assessed. The roughened nickel film is fabricated by electrodeposition using carbon nanotubes (CNTs) as the roughening agent and a polyphenylenesulfide (PPS) resin as the thermoplastic resin. The plated steel and PPS resin are joined by injection molding without adhesive. The bonding strength is determined by a tensile lap shear strength test during the durability tests that includes a high‐temperature and high‐humidity test (85 ± 2 °C, 85 ± 2% relative humidity; 0–2000 h) and a thermal shock test (−50 °C–150 °C; 0–1000 cycles). During the high‐temperature and high‐humidity test, the bonding samples maintain their initial bonding strength (>40 MPa) even after 2000 h. By contrast, during the thermal shock test, although the bonding strength gradually decreases with increasing number of cycles, it remains above 20 MPa even after 1000 cycles. The mechanism of the deterioration of the bonding strength during the thermal shock test is analyzed in detail. The present joining method, which uses a roughened plating film as an interlayer, offers a way to achieve not only high initial bonding strength but also bonding durability for dissimilar material joining between steels and resins.

No abstract

Combining multiple materials is an effective method for decreasing the weight of vehicles and so reducing CO2 emissions to mitigate global warming. Accordingly, techniques for joining dissimilar materials are in strong demand. In the present study, steel and a thermoplastic resin were reliably joined using an anchoring effect with a rough Ni‐plating interlayer. Further details can be found in the article number http://doi.wiley.com/10.1002/adem.202000739 by Susumu Arai and co‐workers.