Update: 10/19/16 10:00 A.M.

Ellen Kullman is sticking to her guns, even if they have been holstered.

The former CEO of DuPont dd hinted that she thought DuPont’s $60 billion deal to merge with rival Dow Chemical is a mistake, speaking Tuesday at Fortune’s annual Most Powerful Women’s conference, which you can watch live here. It was Kullman’s first public appearance since abruptly leaving the chemical giant a little over a year ago.

Kullman didn’t comment on the DuPont-Dow merger specifically, but she said that deals in which companies are put together only to be broken up—which is what is happening in the DuPont-Dow transaction—are the product of short-term thinking, and not what’s best for long-term shareholders or the company.

“Break up, recombine. Break up, recombine,” Kullman told Fortune’s Pattie Sellers. “That doesn’t create any value except for bankers and lawyers.”

In December, a little over two months after Kullman left the company, DuPont and Dow dow announced they were doing a deal. The companies plan to briefly combine the two chemical giants, before breaking them apart again into three separate companies, along business lines. The merger, which is expected to close by the end of 2016, is the first stage in a complicated reorganization that will take years to complete, and will surely produce a lot of fees for investment bankers and lawyers.

As CEO, Kullman repeatedly said DuPont benefitted from its independence and from its multiple lines of business. Dow’s CEO Andrew Liveris approached her a number of times about a combination, starting in November 2014, and again in May 2015. Kullman rebuffed the deal talk. Activist hedge fund manager Nelson Peltz—who took a large stake in DuPont back in 2013 and fought an unsuccessful proxy battle with the company in 2015—was also pushing for the company to do a deal.

(For more on DuPont’s bitter proxy battle, read Fortune’s feature story How DuPont Went to War with Activist Investor Nelson Peltz)

But just months after Peltz’s lost his proxy battle, he indicated that he would soon launch another one for the following year. Kullman said she was surprised at how personal Peltz made the proxy fight, and saw the dynamic as a sign that it was time for her to go. “[Nelson Peltz] very much made me the issue,” said Kullman. “I felt at that point and time that I was getting in the way of the future of the company.”

Shortly after Kullman left, Liveris and Peltz teamed up to work out a deal with Ed Breen, who replaced Kullman as CEO. The WSJ has reported that the negotiations to combine Dow and DuPont took place at Peltz’s mansion in Florida.

At Fortune’s Most Powerful Women Summit on Tuesday, Kullman also suggested that she was disappointed that Breen ended up doing the deal Peltz wanted.

At the time Breen was nominated along with four other board members at the height of the proxy battle with Peltz, Breen and the other nominees seemed to share Kullman’s vision for DuPont, even though Peltz had tried to hire Breen, as well as another board member Jim Gallogly, as an advisor in the past. It didn’t turn out that way. Kullman was asked whether in retrospect she thought nominating two board members that were allies of Peltz was a mistake.

“We didn’t think [we were doing that] at the time,” said Kullman. “Long story. You don’t want to go there.”

On why she left DuPont: “At some point when you are fighting these fights, you lose your joy a bit. And these jobs are tough. You really need your joy to get up out of bed every morning at 5 AM and do what we do. It just seemed like I was the lightning rod, and it seemed like at that point the best thing for the company was to make a change. . .We knew where this story was going. And a second proxy fight was not in the interests of employees our shareholders or anyone.”

On whether women CEOs are specifically targeted by activist hedge funds: “It didn’t feel like it at the time. There are a lot of tough things that women CEOs have been asked to take on, and have taken on and done phenomenally well with. If it makes us a target, that’s part of life.”

On the reaction inside the company when she left: “It was very humbling for me because there was a lot of outpouring from not only the women but the men at the company. Because we had been through a lot of wars together. When you go through something like that you need to have a team that you still like at three in the morning. That was the hardest part, the people part.”

On Carbon 3D, a company Kullman joined the board of: “3-D printing company. There’s a Ted Talk on it. It’s phenomenal technology. There’s a liquid polymer, and you pull the part out of the liquid based on UV light and a lot technology. It’s an engineer’s’ dream. And it actually has the prospect of going into mid-range manufacturing quantities at a cost that is relevant. So taking 3-D printing out of prototyping and into manufacturing. I love being part of a startup. It’s been a lot of fun.”

Update: The story has been updated to reflect that Ellen Kullman, the former CEO of DuPont, did not comment directly on the DuPont-Dow merger, but was talking generally about activist hedge funds, and deals in which they have been involved.