Page 64 - Plastics News January 2023

TECHNOLOGY

Simple, Cheap Hybrid Technology Joins Galvanized Steel and Polymers

rough nanoscale needle structures on HWT conditions on the tensile shear
the true surface, explained a press re- strength were evaluated and the op-
lease on the university website. When timized strength reached 23 MPa.”
a polymer is applied to the treated The process can be adapted for a
metal in a process called injection- range of hybrid joining applications
molded direct joining, it fills in the tiny in which metal and plastic parts need
gaps and ridges between and within to be permanently bonded, said sen-
he technique discovered by re- the needle structures, thereby creat- ior author Yusuke Kajihara. "Further-
Tsearchers at the University of To- ing very strong mechanical linkages. more, our method does not use harsh
kyo does not use harsh chemicals or "We found that immersion in hot wa- chemicals or complicated procedures
complicated procedures.Composite ter was a simple and effective method and, thus, is suited to the scale-up
materials are popular in automotive for producing nanoscale structures on required for industrial applications,”
and other applications to reduce the the zinc coating for the polymer to ad- added Kajihara. This work could lead
weight of components while enhanc- here to, but that prior acid-washing to to optimization of polymer-metal
ing durability. Bonding polymers with remove the passive layer was a neces- joining, which would be a significant
galvanized steel poses some prob- sary step for this to occur," explained asset to the manufacturing industry-
lems, however, as it requires harsh the paper’s lead author, Weiyan Chen. account, among other things,” says
chemicals and specialized equipment, The group also showed how the ten- Wenz. The initial pilot projects with
and is ill-suited to mass production sile-shear strength increased with the industry partners are also already un-
processes, according to researchers complexity of the nanoscale structures derway. The research team expects
at the Institute of Industrial Science on the galvanized steel surface. By op- that initially, programmable materials
at the University of Tokyo. They have timizing the hot water temperature will act as replacements for compo-
developed what they call a cheap and treatment time to achieve peak nents in existing systems or be used
and simple hybrid joining technology complexity in the nanoscale structur- in special applications such as medical
based on injection molding and a hot- ing, the team was able to significantly mattresses, comfortable chairs, vari-
water treatment. The technique is increase the tensile-shear strength able damping shoe soles and protec-
described in a paper published in the compared with untreated metal. tive clothing. “Gradually, the propor-
Journal of Manufacturing Processes. “We successfully obtained strong tion of programmable materials used
The bonding method entails pre- joints of [galvanized high-strength will increase,” says Andrä. Ultimately,
treating the galvanized steel with an steel] and polybutylene terephtha- they can be used everywhere – from
acid wash and dipping it in hot water. late (PBT) via HWT [hot-water treat- medicine and sporting goods to soft
The acid wash strips the outer pas- ment] with minimal damage to the robotics and even space research.
sive layer on the zinc coating of the zinc coating,” the researchers write
steel, allowing the hot water to form in the paper abstract. “The effects of

UCR scientists develop method to turn plastic waste into potentially valu-
able soil additive

niversity of California, River- dul-Aziz, a UCR assistant profes-
Uside, scientists have moved a sor of chemical and environmental
step closer to finding a use for the engineering, and her colleagues de-
hundreds of millions of tons of plas- tailed a method to convert plastic
tic waste produced every year that waste into a highly porous form of
often winds up clogging streams charcoal or char that has a whop-
and rivers and polluting our oceans. ping surface area of about 400
In a recent study, Kandis Leslie Ab- square meters per gram of mass.

64 PLASTICS NEWS January 2023