The phrase "become difficult to work" is correct and usable in written English.
You can use it when describing a situation or task that is increasingly challenging or problematic.
Example: "As the project progressed, it began to become difficult to work with the outdated software."
Alternatives: "become hard to manage" or "become challenging to handle."
However, if the flour is too well coated the pastry will not hold together and will become difficult to work with.
By this time, she had reportedly become difficult to work with, and had adopted very demanding musical standards for her bandmates.
"It's understandable, for Palestinian people education is about dignity and [the] opportunity for a better life… but if schools don't open it's going to become difficult to work here… thousands of children are going to be stuck at home missing their education, a lot of breadwinners won't take home paychecks that support whole families.
"In general, people like that make a good first impression, but become difficult to work with over time because they feel entitled to special treatment, ignore criticism, and intimidate others," Ryne Sherman, a personality psychologist at Florida Atlantic University, told The Huffington Post in an email.
An unstretched fabric will wrinkle and become difficult to work with as you snug down the stitches.
Gypsum plaster recycling shortens the setting times, changing the workability and becomes difficult to work with it.
What with it being a busy tourist Saturday in the shadow of Big Ben, at times it became difficult to work out which people wearing Union Jack paraphernalia and giving the "peace" sign were racist goons, and which were confused Japanese tourists.
They tend, like any art form, to have some practical boundaries beyond which they become difficult to make work.
It became difficult to go into work, and even harder to actually do any experiments once I was there.
"It's become difficult to produce works, promote them and create visibility," he said.
Drawing a line between 'work' and 'life' is crucial, but not only from the point of view that outside distractions can impede on working time, but that it can also become difficult to fully leave work behind when it's time to rest and play, especially when it's your own business.
